My opponent disconnected from the match and I got the loss

My opponent disconnected from the final match in the tourment and i got the loss

I'm actually done with this game i don't want to play it anymore how is that fair ? 

I put time and effort to finish the objective and the tourment is so sweaty and when i actually win this happns?

If no one is helping me here i'm actually uninstalling it 

Here is a proof in the video below!