When a player is injured dosen't mean he's not playing anymore, he is but not at 100% also yes somehow is bug, you can win easy a game without a GK
Just happened earlier in my league, one team had GK injured when score was 0-0, Then that team playing with 10 players went onto win 2-1.
*Retired From Top Eleven*
That's how you win on this game put on an injured keeper