Sixth-placed United are six points adrift of the top four and could miss out on European football completely next season.
Emirates Stadium in London hosted a highly-charged showdown between the leaders, Manchester City, and the fourth-placed, Arsenal.
Arsenal found themselves against the ropes when they trailed 2-0 following goals by Manu Trigueros and Raul Albiol before having Dani Ceballos sent off.
The two players were included in Arteta’s squad for the Europa League.
Arsenal teenager Bukayo Saka scored one goal and set up another as the Londoners sealed a place in the FA Cup fifth round with a 2-1 win over Bournemouth at the Vitality Stadium on Monday.