Danny Welbeck returned to Manchester United as Arsenal’s match-winner as the FA Cup holders sealed a semi-final place at Wembley.
England striker Welbeck joined Arsenal from United in a £16m deal on deadline day in September, and came back to score the goal that gave the Gunners their first win at Old Trafford since 2006.
It ensures Louis van Gaal, the manager who sanctioned his sale, will almost certainly end his first season empty-handed.
Nacho Monreal gave Arsenal a first-half lead but Wayne Rooney equalised with a flying header from Angel Di Maria’s cross, the high point of the Argentine’s night as he was later dismissed for two yellow cards after Welbeck had restored Arsenal’s advantage.
And on a great night for manager Arsene Wenger after United had won 11 of the last 15 meetings between the sides in all competitions, Arsenal are now huge favourites to reach another FA Cup final after drawing either Reading or Bradford City in the semi-final.