For Man United, Bayindir did make several saves in this match.
However, in the end, Man United still lacks in their attacking lines; their sharpness and effectiveness are quite lacking. We must evaluate this to optimize it. They're already quite good in terms of ball possession and attack, but they've managed zero goals from that many shots.
On the other hand, Arsenal's players performed quite well, especially David, with many saves. While their play didn't seem particularly solid, fortunately their back line was very alert, allowing them to thwart various dangerous attacks from Man United.
Bayindir played well against Arsenal, but he missed and Manchester United lost the first match, this also matters, it is difficult to start with a loss. Yesterday I saw that Manchester United are thinking about bringing De Gea back, I think it would be a smart move, they need a better goalkeeper, and Bayindir is still young and needs time to gain experience. Moreover, if Manchester United sets big goals for themselves, they only need the best players, and I think De Gea proved in Fiorentina that he is as good as before.