The question is, what changes did you make after he got red cards? That's important.
Because when I was playing against 10 men, I changed to a more attacking formation and beat my opponent (I was losing).
First I was in defending tactic, when I was 11vs10 I became attacking and stayed attacking during all the match...
Nothing to do even after when I was 11 vs 9 !
Last 30 minutes I decided to play with long passes because he had 2 players less but it changed nothing...