Question: Let's imagine that yesterday there was a match between England and Brazil. I want to say a conditional sentence about the result of yesterday's match, but I don't know the result of the match. If I say "`If Brazil had won the game, they would've gone to the quarterfinal`", it means that they lost the game and I know the result. How can I change that sentence?

Answer: 
I would say, "If Brazil won the game, they will be going to the quarterfinal." 
Since you are talking about yesterday's match, I'm assuming the quarterfinal hasn't happened yet. 

If the match under discussion and the quarterfinals had both already happened, "If Brazil won the game, they would be going to the quarterfinal" or "If Brazil won the game, they would go to the quarterfinal" works better. I have heard this phrasing in documentaries about sports which were written long after the games, but were still trying to create some feeling of suspense.
*"If Brazil won yesterday's game, they'll go to the quarterfinals."*

That is: If something in the past has happened, then something in the future will happen.

Alternatively, if either of the teams will move on to the quarterfinals as a result of that game, you could also say *"Whoever won yesterday's game will go to the quarterfinals."*

You'd only want to say "would've gone to the quarterfinals" if the quarterfinals also already happened.