9. Frankie Edgar Over BJ Penn
When Frankie Edgar fought BJ Penn for the first time at UFC 112 on April 10, 2010, Penn was in the midst of a truly dominant run at 155 pounds. While he had had mixed results at welterweight, Penn looked unstoppable as a lightweight. He had avenged his only loss at that weight (a majority decision setback to Jens Pulver way back in 2002), and had stopped the four challengers he faced since claiming the title.
Edgar, meanwhile, was 6-1 in the UFC with only two stoppage wins. His most impressive victory was a decision over former champion Sean Sherk, and he was coming into his title fight off a win over the unremarkable Matt Veach. Edgar opened as nearly a 6-1 underdog and closed as a 7-1 dog.
Penn likely landed the harder shots, but Edgar’s in-and-out movement, volume, and sneaky wrestling prevented Penn from really getting in gear. Edgar took a controversial decision, and in doing so ended Penn’s reign of terror at lightweight for good. Edgar would win their rematch much more convincingly on the way to becoming an all-time great.