 On the July 25 episode of Raw , Mysterio won the tournament to become the new WWE Champion , and immediately had to fend off Alberto Del Rio to prevent him from cashing in his Money in the Bank . Triple H , now Chief Operating Officer , decreed that Mysterio was to face ex @-@ champion Cena later that night for the title ; Cena won and again became WWE Champion . After the match , Punk made an unannounced return to WWE with the old WWE Championship belt to confront Cena . Cena and Punk later fought in a match at SummerSlam on August 14 to crown the undisputed WWE Champion , which Punk won . As Punk celebrated , Kevin Nash made his WWE return and assaulted him . Del Rio then cashed in his Money in the Bank contract and pinned Punk to become the new champion after kicking Punk in the head . Punk regained the WWE Championship from Del Rio at Survivor Series in November 2011 ; starting a 434 @-@ day reign until The Rock beat him at the 2013 Royal Rumble event . 
