I don't normally do predictions for fights due to the high variance of the sport, but Weidman should be able to finish him (why isn't submission an option, btw?). They trained together and the word there was that Weidman schooled him (GSP himself admitted as much iirc) and when Weidman was asked about it, he said flat-out that GSP is too small for him. His size would be a big advantage at a catchweight or MW. Weidman said he would never call out a smaller guy and they're Renzo Gracie students, training partners, and coached by Danaher, who won't allow them to fight each other. Weidman is the superior grappler, even though St-Pierre is the better striker and has some great grappling himself. No one has gotten the better of Weidman in that department in MMA (or striking for that matter). He made Munoz and Silva look like novices on the ground and for the grappling exchanges against Maia, Weidman definitely got the better of them. He's a prodigy in grappling. He has arguably only lost 1 round in his MMA career (first one against Sakara - he had broken ribs and took it on short notice, couldn't train properly). At best the first round with Maia was 10-10. A judge had 10-10 for the 2nd round with Araujo due to a deep kneebar, but I still thought Weidman won the round overall.