Brock Lesnar WWE UFC
Before Brock Lesnar returns to the UFC, he'll defend his Universal Championship at SummerSlam 2018. Pictured: Lesnar walks to the Octagon for his fight during UFC 200 at T-Mobile Arena on July 9, 2016 in Las Vegas. Rey Del Rio/Getty Images

The card for SummerSlam 2018 is still coming together, but we do know which WWE superstars will be fighting for the company’s top titles. Brock Lesnar will defend his Universal Championship against Roman Reigns, and Samoa Joe will challenge AJ Styles for the WWE Championship.

Reigns defeated Bobby Lashley in a No.1 contender’s match on “Monday Night Raw” to earn his title shot. “SmackDown Live” general manager Paige named Joe as Styles’ opponent Tuesday night.

Neither match comes as much of a surprise, though the reaction to the two matches has been quite different.

Reigns will challenge Lesnar for the top belt on “Monday Night Raw” for the third time this year. Lesnar defeated Reigns clean at WrestleMania 34, and he won a steel cage match against the Shield member just a few weeks later at The Greatest Royal Rumble event. Reigns and Lesnar had their first world title match in the main event of WrestleMania 31 when Seth Rollins cashed in his Money in the Bank briefcase to become the WWE Champion.

Lesnar pinned Reigns to retain his Universal Championship at last year’s SummerSlam, though it wasn’t a singles match. Braun Strowman and Samoa Joe were also involved in the fatal-4-way main event.

Strowman currently owns the Money in the Bank briefcase, and he could insert himself into the Universal Championship Match. Don’t be surprised if he leaves Barclays Center on Aug. 19 with the title.

Since even before he fought in the main event of SummerSlam 2017, Joe has been among WWE’s top performers. His feud with Lesnar last year that culminated with a match at Great Balls of Fire in July was probably the best of the Universal Champion’s current title run. Joe has never held a title on WWE’s main roster, and he’s the most logical challenger for Styles at the biggest remaining event on the 2018 wrestling calendar.

Styles’ current title reign will reach nearly 300 days when he steps inside the ring at SummerSlam. He’s defeated the likes of Rusev, Shinsuke Nakamura and Kevin Owens for the longest WWE Championship reign since CM Punk held the belt from November 2011 until the 2013 Royal Rumble.

Styles defeated Owens at last year’s SummerSlam. He pinned John Cena clean at SummerSlam 2016.