In an interview on Wednesday with "Beatdown" radio on Sherdog.com, St-Pierre denied he greased and will gladly offer a rematch with Penn.
"Let's do a rematch with BJ Penn," St-Pierre said. "We're going to do it this summer. St-Pierre-Penn III -- and this time we'll wear a rash guard. I guarantee you the result will be the same or even worse for him."
By Thursday evening, Penn left a message on his official website BJPenn.com accepting St-Pierre's challenge.
"For the past several days I have been reading statements made by St-Pierre and Greg Jackson about our fight on Jan. 31," Penn said. "St-Pierre claims that he 'is not a cheater' and that he and Greg Jackson will have 'no problem with a rematch in the summer of 2009.'
"To the untrained eye the grease might not look like much but every grappler knows the effect that it has. Being able to apply your submissions and sweeps or just being able to hold on to your opponent to defend yourself from being hit is absolutely critical!
"There is a reason why you are not allowed to put grease anywhere on your body except for the area around your eyes. Because of the grease applied to St-Pierre's body the Nevada State Athletic Commission's executive director, Keith Kizer has stated that the Penn-St-Pierre fight 'definitely wasn't fair.' I hearby accept Georges St-Pierre and Greg Jackson's challenge for a fight in the summer of 2009. Let's call Dana now and set it up."
The fight is now in the hands of UFC president Dana White if he chooses to promote it. While the general consensus is that St-Pierre would have defeated Penn regardless of the effects of the grease, the entire feud has been elevated to the point that a third encounter could match or exceed the success of UFC 94.
Summer may be too soon though, as both fighters already have a title fight on the horizon. St-Pierre will defend his welterweight belt against Thiago Alves, while Penn will defend his welterweight title against Kenny Florian.