This happened to me before in CUP. I won the first leg with 2:1. I was a little bit weaker than my opponent. His quality was about 40 back then. I was almost 40.
Neither of us watched the first game. However, in the second leg, I won the game with a 10:0. Neither of us watch the game too.

Well, I guess this just because he had already quit the game. He is now 43.4 quality in lvl8. I am 43.5 in lvl5. His rank is 13 in his league.