Arsene Wenger claimed his first ever Premier League victory over Jose Mourinho and ended Manchester United’s long unbeaten run.
Arsenal cruised to a comfortable 2-0 win at the Emirates Stadium to inflict United’s first defeat in 26 games since their hammering at Chelsea in October.
Liverpool had been held to a goalless draw by Southampton at Anfield earlier in the day to place a top-four finish back within the Manchester club’s grasp.
Win all four of their remaining fixtures and Champions League football would be secured without the need to lift the Europa League trophy later this month.
That mission began here then at the Emirates Stadium but Mourinho was not making life easy for himself by making wholesale changes to his team.
Only three players who started the semi-final first leg win over Celta Vigo started in north London as teenager Axel Tuanzebe was handed his full debut.
Arsenal’s fading top-four hopes would be over if they lost again after their damaging derby defeat to bitter rivals Tottenham last weekend.
Gabriel and Olivier Giroud make way for Danny Welbeck and Rob Holding as Wenger stuck with his three-man defensive formation.
Both goalkeepers were forced into early action with Anthony Martial and Aaron Ramsey registering shots on target in the first 10 minutes of the match.