#5 John Cena
Upon Brock Lesnar's return to WWE in 2012, he targeted megastar John Cena and the two men squared off at Extreme Rules. The bloody encounter ended with Cena picking up the win, much to many fans' dismay.
Lesnar reportedly caused a ruckus backstage after the match, as he was unhappy with the Cenation leader no-selling his beating. He famously squashed Cena two years later at SummerSlam 2014 to become the WWE World Heavyweight Champion. The latter picked up a DQ win over Lesnar at Night of Champions, courtesy of interference by Seth Rollins.
#4 Triple H
Brock Lesnar kicked off a feud with Triple H following his loss to John Cena. The Beast Incarnate put The Game down at SummerSlam 2012 but the rivalry was from over. The feud was reignited on the road to WrestleMania 29 a year later.
At The Grandest Stage Of Them All, Triple H defeated Brock Lesnar in a No Holds Barred match. Lesnar would go on to put The Cerebral Assassin down inside a Steel Cage at Extreme Rules 2013, thus putting the feud to rest. This was the final in-ring encounter between Triple H and Lesnar.