Who can defeat the incredible Hulk

How did Thanos beat Hulk so easily?

TLDR: We don't know and can only speculate.The film uses this to arouse our curiosity and establish Thanos as a strong villain.

We never see the Hulk build anger. For all we know, he could have just woken up in his bed when he realized the ship was under attack, smashed a few Thanos underlings, and then went straight for him just because he woke up in the middle of a good dream. At least we know that he usually gets angrier when he finds himself in life threatening situations or when the love of his life is in danger. In the MCU, Black Widow comes closest to this and she's not around, nor do we have any evidence that he was in serious danger before he was hit by Thanos.

In the universe he was probably not fully and not very focused. And Thanos is probably at least as strong, with better technique (less emotional fighting style) in this fight. Hulk was probably surprised by how strong his opponent was - and we've seen in Age of Ultron that it's a sneaky way to get him out of the picture for a while if he's not surprised / focused / at full throttle.

Hulk wasn't ultimately defeated to death, but a spaceship is also a terrible place for the MCU Hulk to fight. So far we have no evidence that he would survive in space. Even if it did, breaking the ship apart would kill the remaining Asgards. And this would likely happen if he completely "rested" and engaged in an all-out battle against someone who is at least as strong. In his "mentally improved" state, in which he can speak and recognize "friends" correctly, he might have deliberately held back. In any case, it was probably a wise decision to just send him away and not drag out the losing battle.

Concentrated outside the universe the film does not explicitly focus on him or his mental state. What mood he is in, what fights he used to have, whether he has just transformed, whether or not he already disagrees with Banner. There is not much fuss about the fight or "preparation" on the Hulk's side. This begs the question of how did he lose and why is he hiding in Banner as a Mystery Box so the next movie can be opened and examined, while he and Thor are used for the time being to determine how powerful Thanos is. Up until that point, these two were the top contenders for the "Strongest Avenger". So it sends a strong message when Thanos hits both (!) Completely - individually.

Personal side note : I hope Hulk can take up this relationship between Gimli and Legolas again, solve his mental problems and also "rise up" after Thor intensified his game in Ragnarok and IW.

Chloe

Dreaming is speculation. No evidence presented. It is also not plausible to sleep because of your attacked ship that is on board. It's a plot hole and bad writing.

Dark wing

@Chloe Obviously it's speculation, that's my whole point, we have no idea what happened before. It's absolutely not a plot hole or bad writing, it's just an omission (so yeah, a hole in the sense that we don't see it ^^) because it's not important to the film's story. In fact, it's a nice tool to get people interested in yourself. Whether it is used well all depends on whether and how you come back to it. The whole "Hulk Hiding in Banners" story makes it very likely that we'll see some sort of story arc about Hulk's defeat in the next movie.

Dark wing

@Chloe, it would be a plot hole if Hulk later flipped Thanos with nothing in between that explains the difference between the old and the new situation. But that he loses a short round of combat doesn't contradict what we know from the movies. He was even knocked out by the Hulk buster.

Garet Claborn

This is the correct answer