I'm by no means an expert on Super but I believe Champa wins. My reasoning for this is that Vegeta was going toe to toe with Toppo who had just reached the Hakaishin level, so I think he's still a fair bit weaker than all the other GoDs who had plenty of time to get adjusted to the use of Hakai energy. According to the manga Beerus is also implied to be one of the strongest among the Gods, and Champa is supposedly not far behind him, although I don't know how the manga and anime continuities fit with each other at all.
I think only MUI Goku is above the level of the GoDs based on what the V-Jump insert said about him, but my memory is hazy and we'll have to wait for actual feats to determine that. Either way, I think Champa wins with mid-high difficulty.
Although I wonder if Vegeta's Explosion would be enough to bring him down...