One of the interesting things about the Thanos fight was that Thor and Rulk didn't go down. Everybody seems to have knocked out the new weaksauce-brand Thor lately and Rulk seems to job a hell of a lot too. In fact there was a general lack of heavy hitters since Hulk and Groot were the only other characters there capable of really doing anything. Wolverine, who has been able to damage Thanos, wasn't there. Given the other characters present weren't really capable of much I guess Hulk and Groot must have done most of the hard work in trashing Thanos, and some help from Thor.