I mean he did really well, but it was against a league 1 side late on when they were knackered and chasing the game, so had basically given up on defending. I wouldn't put too much judgement or weight on it aside from that it can't possibly have done his chances of game time any harm
Would like him to get more chances as he's clearly got some ability, but we have Antony, Rashford, Sancho, Garnacho, Martial, Elanga who can all play wide positions, Fernandes who ETH will use on the right when his tactics suit, and hard to see how there'll be many games where there aren't any of those names ahead of Pellistri.