Thanos is a beast, but through purely physical means (aka slugfest) how does he put those two down? Both have insane regen, Colossus has the unstoppable enchantment and hulk just keeps getting stronger. Both are immortal. Both amp up the more bloodlusted they become, so the longer the fight the more it favors the two. hulks gets angrier and colossus causes more destruction equals a win for the team. These are the last two heroes you want to engage in a straight up brawl.
Thanos using all his powers wins...but in a slugfest against these two monsters, after a long long fight I see the team outlasting him.