So I'm honestly feeling like shit here. 

I play magic the gathering, the multiplayer commander format (instead of 1v1, it's usually 4 players all playing each other). I was in a group with 3 guys. Let's call them Jack, Harry and Fred.

Fred was playing a newish deck that he hadn't played much, and was basically out of the box new. Harry was playing a dirty deck that would just control everyone else play, and Jack was playing a mid range deck (so not broken, but not weak either). I was playing my deck, that while not broken, can win combo style, and is protection/control (I like my stuff, dont destroy my stuff style deck). I'd worked hard on my deck, and I'm proud of it. 

Harry talks his game way too much. He encouraged Fred to win by hitting everyone, and Fred kills Harry and Jack. Out of spite, Harry destroys some of my stuff, knowing I cant retaliate, even though it didnt affect him. That's chill, I can get it back.

At this point Harry REALLY wants Fred to win. Hes saying stuff like "this will be easy, just hit her and shes dead," and "you can do this, you can win." I honestly would have just let Fred win at this point, but Harry was jumping around like a jumping bean, and getting on my nerves, offering to help Fred beat me (which is kinda a no no unless you're a new player). Fred was rejecting his help, and Harry's jumpyness was stressing both Jack and I out, and I think it was pissing Fred off too. Harry was also interjecting into things, commenting on Fred's every move, and trying to point out ways to beat me.

This is where I'm not sure if I'm the asshole. Cause I feel like one.

Fred goes to attack me, and I wipe his board. He looks defeated, since that was the way he was going to win. I didnt have to wipe it, I could have just let the damage through and lost. But Harry, the way he was jeering, it hit something inside of me, and I was tired of his bullying (in other games he targets me, because I have "broken cards"). 

I continue to stop Fred from winning until I myself win. Fred looked so sad and defeated and angry at himself. Harry was comforting him, saying that he did well, and that he would help him teach his deck. Fred refused, and I honestly felt like harry was being condescending. I left afterwards, because I felt like a monster. I apologised, and said he did do well, and that we learn from our defeats (hes beaten me before, and I learnt from those losses, which is why my deck has gotten a lot better). 

I feel so angry and sad. Am I the asshole for winning because someone else was taunting me and cheering on my opponent? He didnt deserve it. Harry just pushes my buttons, and I've been nothing but nice to him, but after tonight, I feel like a monster of the way I acted. 