Arsenal scored twice from corner kicks to hand Manchester United manager Ruben Amorim his first defeat in English football on a busy Wednesday night of Premier League football.
In other fixtures, Manchester City ended their miserable run of seven matches without victory by beating Nottingham Forest 3-0 at the Etihad Stadium, while Newcastle snatched a last-gasp 3-3 draw with Liverpool and Joe Aribo scored for 10-man Southampton as they slumped 5-1 at home to Chelsea.
Defenders Jurrien Timber and William Saliba did the damage at the Emirates Stadium as Arsenal cut Liverpool’s lead to seven points.
The Gunners are third in the table with 28 points, level on with Chelsea, while Manchester United dropped to 11th.
Mikel Arteta’s side took the lead in the 54th minute when Declan Rice’s corner was headed in at the near post by full-back Timber.
Saliba then sealed the win when Thomas Partey headed Bukayo Saka’s corner against the French defender’s back and the ball went past Andre Onana in the United goal as Arsenal beat United four times in a row in the league for the first time ever.
At the Etihad Stadium, first-half goals from Bernardo Silva and Kevin de Bruyne put Pep Guardiola’s side in command by the break, with Jeremy Doku adding a third 12 minutes into the second half.
The result took champions City to fourth spot, nine points behind Liverpool, as Forest, who had Nigeria international Ola Aina in their starting line-up as usual, stay in sixth.
At St James’ Park, Fabian Schar hooked in a late equaliser as impressive Newcastle held Liverpool to a six-goal thriller draw.
The Reds thought they had done enough to secure a victory that would have maintained their nine-point lead at the top of the table after twice coming from behind before Mohamed Salah put them 3-2 ahead with seven minutes to go.
But Schar volleyed in from a free-kick that Caoimhin Kelleher came for but failed to claim to ensure a deserved point for Newcastle.
At St Mary’s, Super Eagles midfielder Aribo pulled Southampton level to 1-1 in the first half, but Chelsea went on to add four more as centre-back Jack Stephens was sent off six minutes before the break.
Jadon Sancho scored his first goal for Chelsea as they ruthlessly capitalised on a series of Southampton errors, the Manchester United loanee wrapping up the scoring for the Blues after goals from Axel Disasi, Christopher Nkunku, Noni Madueke and Cole Palmer had put them in control.
While Chelsea are flying high in second place, the Saints are rock bottom, seven points from safety.
In other Premier League matches on Wednesday night, Everton thrashed Wolves 4-0, while Aston Villa defeated Brentford 3-1.
RESULTS
Arsenal 2-0 Manchester United
Manchester City 3-0 Nottingham Forest
Newcastle 3-3 Liverpool
Southampton 1-5 Chelsea
Everton 4-0 Wolves
Aston Villa 3-1 Brentford
