Brock Lesnar defeated The Undertaker at WrestleMania 30, marking one of the most surprising moments in WWE history. More than 15 months later, the Deadman has returned for his rematch with the baddest man in wrestling, and it’s anyone’s guess who will win their match at SummerSlam 2015.

Lesnar was set to defeat Seth Rollins at WWE Battleground and regain the WWE World Heavyweight Championship, but interference from The Undertaker resulted in a no contest. Now the two superstars are set to face off in the main event of the year’s second-biggest pay-per-view.

The build towards their WrestleMania 30 match, as well as the match itself between Lesnar and The Undertaker, was underwhelming. But that might not be the case this time around, and the confrontation between the two on “Monday Night Raw” might have been the show’s best segment this year.

Why Lesnar Might Win

In many ways, it doesn’t make much sense for Lesnar to lose. The Undertaker has already established himself as one of the most iconic stars in WWE history, and while Lesnar isn’t an up-and-coming star that needs a rub, he’ll be wrestling in main events for a few more years. The Undertaker continues to make yearly returns, but it appears to be a safe bet that WrestleMania 32 will be the site of his last match.

Because he is so popular, Lesnar doesn’t necessarily “need” to win any match. But a loss could damage what WWE has built in the former UFC champion over the last year and a half.

Ending The Undertaker’s unbeaten WrestleMania streak helped turn Lesnar into an unstoppable force that WWE has never seen before. Since then he’s had matches with John Cena, Seth Rollins, Roman Reigns and Kofi Kingston, dominating all of them in one-sided matches. Even when he lost the WWE World Heavyweight Championship at WrestleMania 31, Lesnar was protected as Rollins pinned Reigns in a triple threat match.

A loss for Lesnar at SummerSlam would mark three consecutive PPV matches that he could not win. Doing so would derail much of the momentum that Lesnar has built over the last year.

Why The Undertaker Might Win

While the unstoppable Lesnar shouldn’t be losing to a 50-year-old wrestler that he’s already beaten, having The Undertaker get pinned by Lesnar for a second time isn’t an ideal scenario either. Most fans were upset that The Undertaker lost at WrestleMania 30, and many of the casual fans would be happy to see him take down Lesnar.

The Undertaker is one of the most beloved WWE superstars of all time, and his WrestleMania streak was iconic. If he’s going to face the man that finally beat him, traditional booking says that the babyface Undertaker will get his revenge.

Even if Lesnar loses, it will still be a major event whenever he has a match. He’s already beaten The Undertaker once, and he hasn’t been pinned since losing to Triple H at WrestleMania 29.

Who’s Favored To Win?

The betting odds at Paddy Power list Lesnar as the favorite with 4/7 odds. But The Undertaker’s 5/4 odds still give him a good chance to win the rematch.

Who Will Win?

Now that The Undertaker will face Lesnar again, he should get his win over the wrestler that conquered The Streak. But it doesn’t have to happen at SummerSlam.

There have been rumors that The Undertaker will face either Lesnar or Sting at WrestleMania 32. While seeing the Deadman take on the former face of WCW is a dream match for many, having a third and final match between Lesnar and The Undertaker might make the most sense. A decisive win for Lesnar at SummerSlam would keep Lesnar looking strong, but a victory for The Undertaker in 2016 would be the proper end to this feud.

SummerSlam Prediction: Brock Lesnar over The Undertaker