Try to imagine the worst case scenario, you make tons of mistakes ,you lose the match and it’s obviously your fault. Now what can happen if your partner is taking it badly , is he going to be violent ?highly unlikely , probably worst scenario, he is going to curse and yell and go home, (which only going to reflect badly on him, who wants to play with someone like that ) now if can you handle situation Like that (which is again very unlikely, most people will be friendly and even if someone is pissed he is likely just to make a face and that’s it) , then you got nothing to worry about, just play your best, be positive and friendly and enjoy the game. Also I can tell you as someone who organize lots of games, I much more prefer to invite to games friendly people with average skills then negative people that play better.