UFC 94

Georges St-Pierre lands a right cross to the head of B.J. Penn during their UFC welterweight championship fight Saturday night in Las Vegas.   (Eric Jamison / Associated Press)

Georges St-Pierre improved his record to 18-2 with a dominating performance Saturday night against B.J. Penn, who is on canvas pinned against the octagon.  (Eric Jamison / Associated Press)

Georges St-Pierre lands a left against B.J. Penn during their UFC welterweight title bout Saturday night in Las Vegas.   (Eric Jamison / Associated Press)

Georges St-Pierre celebrates his fourth-round technical knockout of B.J. Penn in their UFC welterweight title fight Saturday night in Las Vegas.   (Eric Jamison / Associated Press)

Referee Yves Lavigne ends the fight as Thiago Silva loses by technical knockout to Lyoto Machida (not pictured) in the first round of their UFC light-heavyweight bout Saturday night in Las Vegas. Machida improved to 14-0 while handing Silva his first loss in 14 fights.  (Eric Jamison / Associated Press)

Referee Yves Lavigne tries to separate Lyoto Machida from Thiago Silva in the first round of their UFC light-heavyweight bout Saturday night in Las Vegas.   (Eric Jamison / Associated Press)

Lyoto Machida has the upper hand against Thiago Silva during their February 2009 UFC light-heavyweight fight in Las Vegas.   (Eric Jamison / Associated Press)