On July 21, he made a surprise appearance at a joint WWE-Mattel panel at the San Diego Comic Con. During his appearance, Punk mocked the Chief Operating Officer Triple H and also offered a match to the WWE Championship tournament finalist Rey Mysterio as long as the match took place in Punk's hometown of Chicago. The WWE Championship tournament was won by Mysterio on the July 25 episode of "Raw" but he lost to Cena later in the night. When Cena won, Punk returned to upstage Cena's WWE Championship victory celebration which lead to a title dispute. Triple H later supported the fact that both Punk and Cena's claims as the WWE Championship as legitimate and he scheduled a match between the two at SummerSlam to decide who would become the undisputed WWE Champion. At SummerSlam, Punk was able to win the match but he lost the championship shortly after when Kevin Nash attacked Punk and Alberto Del Rio cashed in his Money in the Bank contract. On "Raw" the next night, Punk accused Nash of working with Triple H to try and keep Punk away from the WWE Championship. After many confrontations between the two, Punk and Nash demanded that they face each other at Night of Champions and Triple H agreed. Triple H would later change the match and would book himself to replace Nash instead after Punk continued to verbally attack him and his wife Stephanie McMahon.