Look, it obvious you have a lot to correct, because you are a low level player, but, in a more level-blind analysis, you were left out on the other side of the court and your opponent did a completely unexpected shot that turned out great, your partner is correct in applauding the guy. so it's nothing to worry about. You should be more mindful of being active in the court because for a moment you just watch your partner play but that's about it I'd say.
Would this have happened if you observed proper court position? of course not, but you wouldn't be playing this match if that were the case.