John Cena vs. Alberto Del Rio: Winner and Reaction from WWE Hell in a Cell 2015

The open challenge for the WWE United States Championship proved to be a problem for John Cena, who lost the title to the returning Alberto Del Rio at Sunday's Hell in a Cell pay-per-view. 

Cena began the show anxiously awaiting the arrival of his mystery opponent but was instead greeted by Zeb Colter. After a brief monologue, Colter announced the arrival of Del Rio.

WWE's official Twitter account provided video footage of Colter welcoming back Del Rio:

Del Rio, who last appeared on WWE television in August 2014, had a feud with Colter in 2013 that ended with Del Rio making Jack Swagger submit during an episode of Raw. 

Upon making his return to WWE, Del Rio issued a brief note to fans on Twitter:

Once the match started, Del Rio was in control, taking the action to Cena and nearly defeating the champion multiple times prior to finally getting the pinfall after a backstabber that was followed by a side kick to Cena's face.

Following Del Rio's huge victory, WWE captured video footage of the elated new champion raising the belt high in the air:

This is a huge moment for Del Rio, who always showed promise during his first WWE run but was never able to reach his potential.

WWE gave Del Rio chances to become one of the company's faces. He won the 40-man Royal Rumble in 2011 and had two WWE title runs. His return Sunday was the beginning of a new day for the Mexican sensation.

This also continues a trend for Del Rio, who has now fought Cena at Hell in a Cell three times—in 2011 (Triple Threat match with CM Punk), 2013 and now 2015. 

It also appears to be a new beginning for Colter, as WWE captured this moment between him and Del Rio after the match:

In defeat, Cena now faces a lot of questions. His title reign lasted just over one month after he defeated Seth Rollins at Night of Champions. 

The obvious move would be for Cena to invoke his rematch clause again, as he did when Rollins defeated him at SummerSlam. Since WrestleMania season is rapidly approaching, though, Cena may want to start setting his sights higher.

Del Rio has a new life in WWE. He started it by knocking off the company's biggest star for the United States Championship and now has upward momentum to make this run his most successful.