World Extreme Cagefighting

Rivera made his WEC debut replacing an injured Josh Grispi against Erik Koch at WEC 52.^[5] He lost the fight via TKO in the first round.

Ultimate Fighting Championship

On October 28, 2010, World Extreme Cagefighting merged with the Ultimate Fighting Championship. As part of the merger, most WEC fighters were transferred into the UFC.^[6]

Rivera was expected to drop to Bantamweight and face Takeya Mizugaki on March 3, 2011, at UFC Live: Sanchez vs. Kampmann.^[7] However, Rivera was forced out of the bout with an injury and replaced by promotional newcomer Reuben Duran.^[8]

Rivera faced Reuben Duran on June 4, 2011, at The Ultimate Fighter 13 Finale.^[9] He lost the fight via submission in the third round and was subsequently released from the promotion.

Return to the UFC

Following two emphatic first round stoppages on the regional circuit, Rivera was re-signed by the UFC to face Alex Soto on May 15, 2012, at UFC on Fuel TV: The Korean Zombie vs. Poirier, replacing Azamat Gashimov who was removed from the bout.^[10] Rivera won the fight via unanimous decision (30–27, 30–27, 30–27).^[11]

Rivera was expected to replace Edwin Figueroa against Ken Stone on June 22, 2012, at UFC on FX 4.^[12] However, Rivera was forced out of the bout with an injury and replaced by Dustin Pague.^[13]

Rivera faced Roland Delorme on July 21, 2012, at UFC 149.^[14] Rivera defeated Delorme via first-round KO. However, Rivera later failed his post-fight drug test for an over-the-counter stimulant and the win was overturned to a No Contest.^[15]

After being clipped twice in the first round, Rivera rallied to defeat Edwin Figueroa on February 2, 2013, at UFC 156 in the second round, staggering him before getting a TKO stoppage.^[16][17]

Rivera was expected to face Hugo Viana on April 20, 2013, at UFC on Fox 7.^[18] However, Rivera was forced out of the bout with an injury and replaced by T.J. Dillashaw.^[19]

Rivera was expected to face George Roop on October 19, 2013, at UFC 166.^[20] However, the pairing was shifted to November 6, 2013, at UFC Fight Night 31.^[21] He won the fight via TKO in the second round.^[22]

Rivera was expected to face Raphael Assunção at UFC 170.^[23] However, Rivera was forced out of the bout due to injury.^[24]

Rivera faced Takeya Mizugaki on May 24, 2014, at UFC 173.^[25] He lost the fight via unanimous decision.^[26]

Rivera faced Urijah Faber on December 6, 2014, at UFC 181.^[27] Rivera lost the fight via second round submission. However, the ending was controversial as Faber stunned Rivera with an eyepoke during a standup exchange. The eyepoke went unnoticed by the referee, but immediately preceded the fight ending submission.^[28] Rivera's management team indicated that they planned to appeal the result in hopes that it would be changed to a no contest, and hoped that the UFC could schedule a rematch with Faber.^[29] Ultimately, the NSAC upheld the result of a submission victory for Faber.^[30]

Rivera faced Alex Caceres on June 6, 2015, at UFC Fight Night 68.^[31] He won the fight via knockout in the first round.^[32]

Rivera faced John Lineker on September 5, 2015, at UFC 191.^[33] He lost the fight via submission in the first round. The wild slugfest earned both participants Fight of the Night honors.^[34][35]

Rivera faced Brad Pickett on February 27, 2016, at UFC Fight Night 84.^[36] He lost the back-and-forth fight via split decision.^[37]

Rivera next faced Érik Pérez on July 30, 2016, at UFC 201.^[38] He lost the fight via unanimous decision.^[39]

Rivera received a four-year USADA suspension for testing positive for a banned substance clenbuterol, collected from an out of competition sample on July 23, 2016.^[40] He was subsequently released from the promotion.^[41]

Post-UFC career

Rivera was given a license to compete in California, and was scheduled to fight Trevin Jones at LXF 6 on March 20, 2020, but the event was cancelled due to the COVID-19 pandemic.^[41][42]

Rivera then faced Ryan Lilley at XMMA 8 on January 30, 2021.^[43] He won the fight via first-round knockout.^[44]

Rivera faced Adam Martinez in the first bout of the one night bantamweight tournament at Combate Global: Bantamweight Tournament on May 29, 2021.^[45] He won the bout via KO in the first round of a one round bout. In the Semifinals, he faced fellow UFC vet Nohelin Hernandez, who he defeated via unanimous decision. In the finals, Rivera faced David Martinez, to whom he lost in the second round after being dropped by a head kick and finished on the ground.^[46]

Rivera faced John Dodson on April 2, 2022, at XMMA 4.^[47] He lost the bout via unanimous decision.^[48]

Rivera faced Teruto Ishihara on August 20, 2022, at UNF 2. He won the bout via unanimous decision.^[49]

Rivera faced fellow UFC veteran Cody Gibson at Up Next Fighting 3: Rivera vs. Gibson for the inaugural UNF Bantamweight Championship. Rivera lost the bout via submission in the third round due to an arm triangle choke.^[50]

Rivera returned to XMMA on May 3, 2023, at XMMA 6, facing Ricky Bandejas. The bout ended in a no contest after Rivera was poked in the eye in the second round and was unable to continue.^[51]

On July 1, 2023, Rivera would then face Dana White's Contender Series alum Josh Wang-Kim for the interim UNF bantamweight championship at UNF 9. He won the bout via unanimous decision and became the interim bantamweight champion.