Former UFC welterweight champion Georges St-Pierre has announced that he has officially started the USADA drug testing process so that he can be eligible to fight in the UFC once again.

In a recent interview with Bloody Elbow, “Rush” went over various topics from a rematch with Nick Diaz, to his thoughts on Nate Diaz vs. Conor McGregor.

A couple questions came up about GSP’s past opponents. Rush was asked who he considered his toughest opponent.

“Penn and Condit,” St-Pierre said. “Condit hurt me the most, and then it was mentally a challenge, and Penn also hurt me. People think Hendricks was the toughest, but against Hendricks I was emotionally hurt, that’s what showed on my face. The next day physically I was fine. Against Hendricks I felt I was against the system. I felt the system was corrupted against me, like Dana White was for some reason against me, and I didn’t understand why; I was not trying to put the UFC down, but to bring ‘em up. When I spoke before the fight I wanted to help the sport, I wanted to help the UFC, so that’s what showed, what was emotionally, mentally in my head. I felt the system was against me and I didn’t understand why.”

When asked about who he considers the best welterweight of all time next to himself, there was only one fighter’s name that “Rush” mentioned twice.

“Hughes or Penn,” St-Pierre answered. “BJ, when he was a welterweight is probably the most talented, when he was trying. Unfortunately, he was inconsistent, not a hard worker.”