Mistakes occur in every sport in virtually every game played. They are a common part of sports, and managing those mistakes is something that every athlete must deal with at times. A momentary lapse in concentration can have disastrous effects on a team and cause entire careers to be viewed in a different light. When the spotlight shines brightest, it can lead to the biggest mistakes, which can put years of preparation to waste.

In an instant, the public’s perception can change from endearment to outrage. In some cases, it has become the sole moment for which the athlete is remembered. An entire lifetime of preparation, practice, and performance washed away in a single error. It is one of the devastating outcomes of being a high profile athlete, and in most cases, completely unfair toward the individual committing the error. Many of these blunders have had life changing repercussions.

While the circumstances facing these athletes were extraordinary, their performances were not, although they were certainly memorable. Many of them occurred on the grandest stages of their respective sports, while national audiences or even the entire world were watching. These mistakes have cost teams championships or the athletes themselves gold medals. This is why they are the biggest mistakes in sports history.

20 20. Jose Canseco’s Home Run Header

There is video evidence of at least one occasion where Jose Canseco used his head. Unfortunately, he is using his cranium to help the Cleveland Indians’ Carlos Martinez convert a fly ball out into a home run. Canseco lost track of the ball as he approached the warning track, before it hit him on the top of the head and bounced over the fence for a home run. In the wake of the header home run, Canseco was offered a contract by the Harrisburg Heat of the National Professional Soccer League. Sadly, it would not be the final mistake that Jose Canseco displayed for the general public.

19 19. DeSean Jackson’s Early Celebration

During the first game of his rookie season, DeSean Jackson rightfully earned his reputation as a player that celebrates prematurely. After beating the Dallas Cowboys defense over the top, he ran towards the end zone following a 60 yard pass from Donovan McNabb. However, just before reaching the goal line, Jackson threw the ball behind him in celebration. The play was ruled a touchdown on the field, but it was overturned in the replay booth. The Eagles managed to score with a 1-yard touchdown run by Brian Westbrook on the next play, but would go on to lose the game to Dallas.

18 18. Gary Anderson’s Miss

Gary Anderson had not missed a kick in nearly two years and was the first player to ever have a perfect kicking season. Anderson went 35/35 on field goals and 59/59 on extra points. However, Anderson could not convert when it meant most, the field goal which would have sent the Minnesota Vikings to the Super Bowl. With 2:11 left in the NFC Championship game against the Atlanta Falcons, Anderson walked on the field to attempt a 39-yard chip shot that would have put the Vikings up by 10. Anderson missed the field goal to the left, which gave the Falcons an opportunity to tie, and they seized it. The Vikings would lose in overtime, leaving Gary Anderson as the goat.

17 17. John Carney’s Missed Extra Point

With only 7 seconds remaining in a game between the Carolina Panthers and the Jacksonville Jaguars, the Saints trailed by 7. The ball was on their own 25-yard line when Aaron Brooks took the snap and found Donte Stallworth streaking down the field. Stallworth broke four tackles before throwing a lateral to Michael Lewis. Lewis pitched it to Deuce McAllister, who then tossed it to Jerome Pathon for one of the craziest touchdowns in NFL history. Seconds later when Carney stepped up to kick the game-tying extra point, he missed it to the right, essentially negating one of the most exciting plays in the history of the league.

16 16. The Play

With only seconds remaining in a 1982 matchup between the Stanford Cardinal and the California Golden Bears, Stanford decided to squib kick a kickoff to prevent a big return. What ensued was one of the most improbable plays in football history that ended with Kevin Moen running through the Stanford band for a touchdown. Stanford took the field with only ten players and the Cardinal special teams unit was unable to tackle any of the Cal ball carriers as they lateraled the ball through the chaos. Moen commenced the celebration by knocking down a member of the Stanford band. The play also has one of the most memorable radio calls of all time thanks to the efforts of Joe Starkey.

15 15. Roberto Baggio’s Missed Penalty

The Rose Bowl in Pasadena, California was the site of the 1994 World Cup Final, which will forever live in infamy for Italian soccer fans. After 120 scoreless minutes, the match went to penalties. Both teams missed their first penalty before converting their next two. Brazil drew ahead on a penalty from Dunga and a miss from Italy’s Daniele Massaro. Roberto Baggio, one of the best players in the world and the tournament’s shining star, stepped up to the penalty spot to force a decisive penalty from Brazil. However, when he went to convert the penalty, he leaned back slightly too far and sent the penalty sailing over the crossbar, resulting in a  devastating moment for both Baggio and Italy.

14 14. Leon Lett’s Blocked Field Goal Blunder

On Thanksgiving Day 1993, the Miami Dolphins lined up to kick a 41-yard field goal that would have given them a 16-14 win over the Dallas Cowboys. Pete Stoyanovich stepped up to kick the field goal, and had his kick blocked by the Dallas Cowboys. As the ball spun to a stop, Leon Lett decided to attempt to dive on the ball, but slipped and kicked it, making it a live ball. The Dolphins went on to recover the ball on the 1-yard line with only 3 seconds on the clock. Stoyanovich then converted the 19-yard field goal with ease, giving the Dolphins an improbable Thanksgiving Day win.

13 13. Wrong-Way Marshall

Jim Marshall was an intimidating part of the Minnesota Vikings’ Purple People Eater defense of the 1960s. However, during a 1964 game against the San Francisco 49ers, Marshall was involved in one of the most embarrassing plays in NFL history. Marshall pounced on a fumble during the game and ran an impressive 66 yards into the end zone, but it turned out to be the wrong end zone. He then threw the ball in celebration, thinking he had scored, but he had actually given a safety to the 49ers. Despite the mistake, the Minnesota Vikings were still able to win the game 27-22.

12 12. Asante Samuel Drops Super Bowl Winning Interception

One minute and 20 seconds remained in Super Bowl XLII when Eli Manning stepped back to pass, in an attempt to lead the New York Giants to a winning drive. The Patriots dropped into coverage and Manning threw a duck to the sideline. Asante Samuel, who led the NFL in interceptions twice, jumped up to intercept the pass, but the ball flew through his fingers and out of bounds. Eli then resumed his drive, David Tyree made a miraculous helmet catch, and the Giants found a way to win the Super Bowl. This play remains one of the most overlooked plays in the history of the league.

11 11. Romo’s Dropped Snap

Tony Romo spent two seasons as a holder before being given a chance to shine as a starting quarterback. In his first season as a starter, he remained the holder and took the Dallas Cowboys to the NFL Wild Card game against the Seattle Seahawks. With 1:19 left in the 4th quarter, Romo stepped onto the field as the holder for a go-ahead field goal attempt by Martin Gramatica. As Romo took the snap, it slipped through his fingers and despite his recovery and efforts to scramble into the end zone, he was stopped at the 2-yard line. Romo has been trying to dodge his reputation as a choke artist ever since .

10 10. Leon Lett’s Premature Celebration

Leon Lett is responsible for two of the most memorable mistakes in football history. His most notable mistake occurred on football’s biggest stage during Super Bowl XXVII. Late in the 4th quarter, Lett recovered a fumble and sprinted towards the end zone. At the ten yard line, he began to slow down and extended the ball from his body in celebration. Lett was unaware of the sprinting Don Beebe, who had hustled the length of the field to knock the ball from Lett’s hands and out of the end zone for a touchback. The play had no impact on the game’s result, but prevented the Cowboys from scoring the most points of any team in Super Bowl history.

9 9. Tom Osborne Goes for Two

The 1984 Orange Bowl served as the spectacle for one of the most memorable finishes in football history. The Miami Hurricanes were a brash and controversial football team, while the Nebraska Cornhuskers were the pride of the Midwest. Needing only a tie to win the National Championship, Nebraska scored in the final minute to make the game 30-31. Rather than settling for the tie and winning the Championship, Tom Osborne elected to go for the two point conversion. The ensuing pass was incomplete, and the Miami Hurricanes won the National Championship, launching a college football dynasty.

8 8. Jean van de Velde’s Triple Bogey

Jean van de Velde held a three shot lead over the competition as he approached the 18th hole at Carnoustie during the 1999 Open Championship. He had birdied the hole on two of the previous days, and needed only a double bogey to lift the Claret Jug. Van de Velde then hit his tee shot, but it landed in the rough. Instead of taking a conservative approach, he hit an aggressive second shot, which ricocheted into knee high rough. His third shot landed in the water hazard, forcing van de Velde to take a drop and a penalty stroke. The next shot landed in the bunker. He then chipped onto the green before making his next putt for a triple bogey. Van de Velde would lose to Paul Lawrie in a playoff, with his 18th hole meltdown earning a rightful place in gold history.

7 7. Lindsey Jacobellis’ Shows Off

Lindsey Jacobellis enjoyed a three second lead in the Gold Medal Final in Snowboard cross during the 2006 Turin Olympics. She had been the favorite and proven her ability throughout the competition. Approaching the penultimate jump, Jacobellis decided to add a little style by throwing in a method, a grab and one of the most basic snowboarding tricks. Upon landing, Jacobellis caught her heelside edge and fell down, which allowed Tanja Frieden to make up the significant gap and capture the gold medal. Jacobellis was forced to settle for silver.

6 6. Chris Webber’s Timeout

Chris Webber was part of the most influential college basketball team of all time, the University of Michigan’s Fab Five. They were the first to adopt baggy shorts and high black socks, and their style has been emulated by players ever since. The Fab Five made it to two consecutive National Championship games, losing both. With 11 seconds remaining in the second Championship game, Webber brought the ball up the court into the waiting North Carolina defense. Michigan was down 2 and had no timeouts remaining, but Webber attempted to call one, resulting in a technical foul and a turnover. Webber would go on to star in the NBA, but the phantom timeout has haunted him ever since.

5 5. Steve Bartman Catches a Foul Ball

The Cubs were only 5 outs away from their first appearance in the World Series since 1945, when disaster struck. Several Cubs fans leaned over to catch a foul ball, but the hand of Steve Bartman deflected the ball, preventing Cubs outfielder Moises Alou from retiring Luis Castillo. The Marlins would go on to score seven runs in the inning, and the Cubs would lose the following game, blowing their chance to appear in the World Series. Bartman was the first in a string of events that conspired against the Cubs, and he remains a pariah among Cubs fans.

4 4. Merkle’s Boner

For over 100 years, Fred Merkle’s name has been synonymous with a mistake that cost his New York Giants the National League pennant. In the bottom of the 9th inning, Merkle singled down the right field line and put the go ahead run on third base. Al Bridwell then drilled a single into center field, allowing Moose McCormick to score from third. However, when Fred Merkle saw the crowd rushing the field, he retreated to the dugout without ever touching second base. This was notice by Cubs 2nd baseman Johnny Evers, who retrieved the ball, or possibly a fake, and stepped on second for the force out. National League President Harry Pulliam upheld the ruling and ruled the game a tie. The Giants lost the ensuing playoff game and the Cubs would go on to win the 1908 World Series.

3 3. Selling Babe Ruth for $100,000

Red Sox owner Harry Frazee was a theatrical producer that routinely needed money to finance his productions. On one occasion, he sold the greatest player in baseball history for $100,000 in order to finance productions of either My Lady Friends or No, No, Nanette. Ruth transitioned from pitcher to right fielder and quickly became one of the most prolific home run hitters in history. The Curse of the Bambino then afflicted the Boston Red Sox, who had to wait until 2004 for another World Series title. Meanwhile, the Yankees went on to win more World Series titles than any other team in baseball history.

2 2. Andres Escobar’s Own Goal

Andres Escobar’s own goal proved to be the most costly act of his life. During the 1994 World Cup, Escobar played for Colombia and in their second group stage match, conceded an own goal against the United States. John Harkes sent in a cross that Escobar stretched to clear, but instead sent directly past Oscar Cordobo and into his own goal. When Escobar returned to Colombia, he spent a night out at a club with his friends. After splitting up with them, Escobar was found alone in the parking lot, where he was approached by a car. An argument ensued and Escobar was shot six times by Humberto Castro Munoz, a bodyguard for a powerful drug cartel leader. Munoz served 11 years for the murder.

1 1. Bill Buckner’s Boot

Bill Buckner amassed over 2,700 hits, but will never be considered a Hall of Fame candidate because of one mistake that occurred during Game 6 of the 1986 World Series. Buckner went 0-5 in the game, but his biggest mistake came in the bottom of the 9th inning, when Mookie Wilson hit a slow ground ball toward first base. Buckner attempted to rush this play causing the ball to roll between his legs and into right field. Ray Knight scored from second base giving the New York Mets the win to even the series at 3-3. The Red Sox would lose Game 7 despite leading 3-0 and Buckner’s place in baseball lore was sealed.