Fighting clean continues to remain an important principle in MMA, as all competitors who took part in Bellator 131 passed their drug tests.

Andy Foster, director of the California State Athletic Commission (CSAC), confirmed on Friday that no fighter tested positive for banned substances after the event, which took place on Nov. 15 at Valley View Casino Center in San Diego, California, according to MMA Fighting. The event aired live on Spike TV.

UFC Hall of Famers Tito Ortiz and Stephan Bonnar served as the main event, which resulted in Ortiz coming out as the victor via unanimous decision.

The co-main event saw Will Brooks obtain his second victory over Michael Chandler, becoming the undisputed Bellator lightweight champion in the process. Another high-profile fight was Joe Schilling vs. Melvin Manhoef, which ended with a knockout victory for Schilling.