Pierre-Emerick Aubameyang’s second-half penalty gave Arsenal their first Premier League away win over Manchester United since 2006.
Aubameyang ended a run of five games without a goal by sending David de Gea the wrong way on 69 minutes after Paul Pogba had fouled Hector Bellerin.
United came closer to an equaliser when Donny van de Beek’s cross-shot flicked off Mohamed Elneny and then into the face of goalkeeper Bernd Leno before bouncing to safety off a post.
United manager Ole Gunnar Solskjaer said there was no excuse to the result on his 100th game in charge.
“We didn’t turn up, especially in the first half. That’s what we have to address because we know these boys can be so good.” Ole Gunnar Solskjaer lamented.
The win takes the gunners to ninth on the table with 12 points while United are 15th .
In other EPL results Gareth Bale scored his first goal after the return to England to give Spurs a 2-1 win over Brighton.
Newcastle beat Everton 2-1 . Southampton and Aston Villa were in a seven goal thriller with the saints winning 4-3.