WWE fans have been treated to a handful of lackluster main events under the SummerSlam chronology. But at the same time, some of the top matches in the 21st century happened to be main events at the ultimate summer party.

We don't know yet what the SummerSlam 2019 main event will be, but we can only hope that it'll top some of the boring ones we've been forced to endure over the past 10 years. In the meantime, let's take a look at how the last 10 main events at SummerSlam stack up against each other.

10 Brock Lesnar Vs. Randy Orton (SummerSlam 2016)

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This marked the very first showdown between two future Hall of Famers with similar wrestling personas. Brock Lesnar and Randy Orton have portrayed vicious, merciless and unforgiving superstars throughout their careers. Pitting these two one-on-one in the main event of SummerSlam 2016 made all the sense in the world.

But WWE completely insulted the intelligence of fans with this main event. Lesnar dominated the match, and there were no true "wow" moments. It was evident the whole time that Orton was going to lose. The match ended in a victory for Lesnar via technical knockout; he attacked and beat Orton to a pulp. So much for a good match, and so much for a great ending.

This was a major disappointment in every aspect.

9 Team WWE Vs. The Nexus (SummerSlam 2010)

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This match was supposed to be a crowning moment for the members of The Nexus - Wade Barrett, Justin Gabriel, David Otunga, Darren Young, Heath Slater, Skip Sheffield, and Michael Tarver.

The up-and-coming superstars were supposed to take down a stacked group of seven WWE superstars in this match, led by John Cena and another young talent in Daniel Bryan.

According to Edge and Chris Jericho, the original call was for The Nexus to win the match. This would help put Barrett over, but instead, they were buried by none other than Cena himself. Team WWE had no reason to win this match. It was a complete botch by the creative team, and Team Nexus lost a ton of momentum and relevance after this loss.

8 Alberto Del Rio Vs. CM Punk (SummerSlam 2011)

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CM Punk defeated John Cena in the main event of SummerSlam 2011, except there was one more match that nobody saw coming.

WWE Hall of Famer Kevin Nash came out after the match and attacked Punk. Taking advantage of the situation, Alberto Del Rio cashed in his Money in the Bank contract and easily defeated Punk to win the WWE Championship.

Now, this "main event" match only lasted five seconds, but the entire cash-in caught everybody by surprise. It was a shocking yet incredible ending to the night. Even if the match only lasted a few seconds, it was still pretty good. This was, hands down, one of the greatest cash-ins ever.

7 Brock Lesnar Vs. Samoa Joe, Roman Reigns And Braun Strowman (SummerSlam 2017)

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Another SummerSlam, another eh-okay main event headlined by Brock Lesnar. Get used to it. We're not even halfway done through the Lesnar-SummerSlam matches over the past decade.

At SummerSlam 2017, Lesnar defended his Universal Championship in a Fatal 4-way match against Roman Reigns, Samoa Joe, and Braun Strowman - three superstars in the midst of big pushes. WWE had the chance to push Joe or Strowman even more in this one, but of course, they botched it.

Related: Roman Reigns Explains Difficulties Of Cutting Promos In WWE

Once again, you just knew the whole time that Lesnar would win the match. There were some fine moments (Reigns put on quite a clinic here), but Lesnar escaped with a victory via pinfall on Reigns. Rinse and repeat. The ending we all expected. Bo-ring.

6 Daniel Bryan Vs. Randy Orton (SummerSlam 2013)

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The original main event of SummerSlam 2013 saw Daniel Bryan challenge John Cena for the WWE Championship - with Triple H acting as the special guest referee. This was an epic bout between the WWE's two biggest stars at the time in Cena and Bryan. When all was said and done, the latter pulled off the victory and became the new champion.

However, Triple H hit Bryan with a pedigree out of nowhere - just as Randy Orton came out to cash in his Money in the Bank contract. That set the stage for Orton to easily pin Bryan and become the new champion.

It was only an eight-second match, but the "shock" and "wow" factors made this a rather memorable main event anyway. Certainly a better SummerSlam main event match than what we've seen over the past five years.

5 Roman Reigns Vs. Brock Lesnar (SummerSlam 2018)

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After being forced to watch a handful of boring main events involving Lesnar at SummerSlam, we were treated to something half-decent in 2018. Roman Reigns - who lost numerous title matches to Lesnar - finally conquered his Kryptonite.

Even though Reigns wasn't still fully accepted by the WWE Universe at this time, he garnered plenty of positive reactions for taking down Lesnar. A key reason why? Probably because fans were sick of a part-timer holding onto the title for well over a calendar year. Finally, the title was around the waist of a superstar who deserved it.

Related: 5 Wrestlers Brock Lesnar Had Beef With (& 5 He Loved)

This truly felt like Reigns' career-defining moment. He took down the unstoppable Lesnar once and for all, and this time, he had plenty of crowd support behind him. This wasn't a flashy match by any means, but it also wasn't terrible. That's all that mattered.

4 Brock Lesnar Vs. Triple H (SummerSlam 2012)

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Lesnar was only four months into his WWE return, so the fans were able to get behind The Beast Incarnate headlining SummerSlam 2012 - especially against a marquee superstar like Triple H.

Overall, the match (a No Disqualification stipulation), was well executed, with both superstars using their finishing maneuvers numerous times. Finally, Triple H succumbed to the Kimura Lock, and Lesnar emerged victorious in a bout that lasted just under 19 minutes.

This wasn't one of the absolute greatest SummerSlam main events of all time, but it got the job done. There simply wasn't much to complain about. It was a fine ending to a great SummerSlam show.

3 Brock Lesnar Vs. The Undertaker (SummerSlam 2015)

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Over a year after Lesnar ended his perfect WrestleMania streak, Undertaker returned and looked for some comeuppance on The Beast Incarnate. The buildup between this match was incredible; including a brawl where Undertaker and Lesnar had to be restrained by the entire WWE locker room and authorities.

Related: 5 Stars The Undertaker Buried (& 5 He Put Over)

But the match itself was lackluster at best. It dragged on for far too long (just under 18 minutes) and the ending was terrible. Lesnar got Undertaker to tap out in his Kimura Lock submission hold, but the referee "missed" it." The chaos distracted Lesnar, who was hit by a low blow before losing by technical submission; Undertaker applied the Hell's Gate hold and caused Lesnar to pass out.

Not a good way to end such a hyped-up match.

2 CM Punk Vs. Jeff Hardy (SummerSlam 2009)

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Jeff Hardy defended the World Heavyweight Championship in a Tables, Ladders, and Chairs match against CM Punk. This was one of the most memorable and epic matches in the history of SummerSlam, not just the second-best main event for the chronology in the past decade.

These two men sacrificed everything for our entertainment. Hardy climbed to the top of a ladder and performed a Swanton Bomb on Punk. The former was about to be stretchered off, but he made one last-ditch effort to climb the ladder and retain the title. However, Punk fought off Hardy and became the new WWE Champion.

As if that match wasn't good enough, Undertaker made an electrifying return before the show ended - hitting CM Punk with the Chokeslam and bringing the crowd to their feet. It was a wonderful conclusion to an excellent night.

1 John Cena Vs. Brock Lesnar (SummerSlam 2014)

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Sure, Lesnar has taken part in many lackluster matches at SummerSlam -- and even WrestleMania -- but nobody can deny that this match against Cena was one of the best performances of his career.

SummerSlam 2014 itself was one of the top shows in the chronology's history. Cena and Lesnar saved the best for last, going back and forth in an epic WWE World Heavyweight Championship match that went on for 16 minutes.

Lesnar dominated most of the match, but Cena's determination and resilience made this bout all the more epic. Lesnar finally won via pinfall after hitting Cena with an F-5. What a remarkable show by these two men. This is exactly what a SummerSlam main event should look like.

Next: 10 Insane Vince McMahon Ideas That Were Rejected By His Staff