5 Opponents who have defined John Cena's career in WWE

Cena is a 16-time World Champion
Cena is a 16-time World Champion

#2 CM Punk

Punk and Cena had some of the best WWE matches of the 2010s
Punk and Cena had some of the best WWE matches of the 2010s

One of the most celebrated feuds of the past decade, the rivalry between Cena and Punk was pro wrestling at it's best. These two were the polar opposite of one another both inside and outside the squared circle. While Cena was always abhorred and ridiculed by the fans for in-ring style, Punk was regarded as one of the best in the world. Cena was always soft-spoken and diplomatic but Punk was renowned for being someone who always spoke his mind. Cena a being a WWE loyalist fed perfectly into Punk's anti-authority persona.

After becoming the leader of The New Nexus, Punk would target a plethora of Superstars on RAW which included Cena. Their match at Money In The Bank 2011 is regarded by many as one of the best matches in WWE history. Punk pinning Cena in front of a raucous crowd in Chicago is a sight that fans will remember for years to come.

The win over Cena helped solidify Punk as a main-event Superstar. After winning the WWE Championship from Rey Mysterio on the July 25, 2011, episode of RAW, Cena's championship celebration would be cut short by a returning Punk who showed up with his WWE Championship. A match between the two was set for SummerSlam. Punk would defeat Cena once again at The Biggest Party of Summer to become the Undisputed WWE Champion.

Cena would unsuccessfully challenge Punk for the WWE Championship during Punk's historic 434-day WWE Championship reign. He would unsuccessfully cash-in his Money In The Bank contract against Punk following interference by The Big Show, thereby earning Cena the distinction of being the first win to not win a championship following a MITB cash-in. Punk successfully defended the WWE Championship against Cena and The Big Show at SummerSlam 2012 and would fight Cena to a draw at Night of Championship.

The Leader of Cenation would finally get one over The Second City Savior as he defeated Punk on the February 25, 2013 episode of RAW with the No. 1 Contendership for the WWE Championship at WrestleMania 29 against The Rock at stake.