You never say never in MMA, as Matt Serra will tell you, but at 170 pounds the strategy GSP employed last night simply can't be stopped. Every time he fights now, Georges just sucks the life out of his opponents. You can see it in their eyes by the end of round 2 or 3 each time.
All things considered, BJ Penn was the optimal skillset to deal with GSP's strategy last night. He has tremendous takedown defense, he's an incredibly advanced black belt, he has the punching power to catch guys for short periods standing up, and he has a great ability to stand up after a takedown.
It's hard to overstate GSP's performance...in fact, you can't. He easily passed the guard of a guy who won the world championships when it counted the most. He took down the guy with the best takedown defense. He outboxed a guy Freddie Roach calls the best boxer in MMA. And he held a guy down that Randy Couture and Matt Lindland couldn't hold down.
The only threat to GSP at 170 is if he lets down his guard or picks a poor strategy. Using the same strategy from last night he will stomp Thiago Alves, though knowing St. Pierre he'll probably leg kick Alves to death for victory, just to prove a point. If not Penn, who has the stylistic answer to St. Pierre at 170 pounds?