Infinity against the league in a straight up fight ends up with Thanos massacring them. Warlock might also be alive if most opening attacks are aimed at Thanos. The fight there wouldn't really be close given they can do nothing to Thanos and he can casually one shot al of them. On the other hand, the Infinity watch with the gems minus Thanos results in blitz. Actaually, I figure warlock has faster than light reaction times, but I can't remember a single scan to prove it. If he does though, he'd need some anti-speed steal feat. Personally, I'd peg good enough energy manipulation and some Thanos light feats good enough, but I'm not sure what others think of that.
Interestingly, if minus Thanos means the Gem holders get switched around and Warlock gets the space gem (assuming he knows how to use it, which he should), he could potentially solo.
Neither is really close per say..