At the end of Avengers: Age of Ultron, Thor went back home to Asgard to find out more about the Infinity Stones and prevent his visions from becoming true. And this will lead directly into the Ragnarok, which is the end of days for the Asgardian gods and the beginning of a new age.
Of course, we all know that the fall of Asgard might happen because of two things. The first one, and the least exciting we might add, is that Loki has taken the place of Odin on the throne and, in a way or another, for a reason or another, is seeking to destroy his home realm.
The other reason is more than exciting and it involves Thor trading blows with a more than worthy opponent.
Thor vs. Thanos

As we have seen also in Avengers: Age of Ultron, Thanos decided to search for the Infinity Stones on his own. And the Tesseract (presumed to be the Space Stone) is in Asgard.
It is more than obvious that this was about time for the Mad Titan to get down from his high-horse (or throne) and get dirty. And Thor and the rest of the Asgardians are exactly in his way.
So who could win in this case, when the God of Thunder faces the Mad Titan?

