Ainsley Maitland-Niles was sent off for Arsenal but late goals from Calum Chambers and Pierre-Emerick Aubameyang gave them all three points.
N'Golo Kante's superb solo effort proved a mere consolation for Chelsea as they lost 2-1 at home to Liverpool in the Premier League.
Ole Gunnar Solskjaer admits Marcus Rashford is likely facing a spell on the sidelines with a groin injury picked up against West Ham.
Manchester United have one win in the past five Premier League games after a loss at West Ham that Jose Mourinho said held no positives.
Aaron Cresswell's goal means David de Gea has conceded more free-kicks than any other goalkeeper since his Premier League debut.
Traces of attacking intent were all too scarce for an apprehensive Manchester United as they turned in a poor away performance at West Ham.
Goals from Andriy Yarmolenko and Aaron Cresswell earned West Ham a 2-0 win against Manchester United at the London Stadium on Sunday.
Unai Emery has made just one change to his starting XI from the side that drew with Watford last weekend for the visit of Aston Villa.
Manchester United manager Ole Gunnar Solskjaer played Jesse Lingard as a lone striker after Marcus Rashford's injury at West Ham.
Benjamin Mendy did not appear to take offence at a post from team-mate Bernardo Silva that prompted accusations of racism.
Plenty of thrilling sporting events are happening this week! For Astro Sports Pack customers, here's a handy guide on what to look out for in the next few days... (coverage is subject to change)
Zlatan Ibrahimovic scored a hat-trick and broke a record as LA Galaxy crushed Sporting Kansas City.
We round up the front and back pages across Europe, as Monday sees the transfer rumour mill crank into gear once again.
In a career that has seen him play for Germany, Chelsea and Werder Bremen, Red Star captain Marko Marin is enjoying his time in Belgrade.
After setting a new LA Galaxy record, Zlatan Ibrahimovic claimed it is easy to score goals if players can "be like Zlatan".
After being accused of rape – an allegation that has since been dropped – Cristiano Ronaldo has spoken about how the matter impacted him.
The spat between Liverpool stars Mohamed Salah and Sadio Mane is over, according to the latter, who has "reconciled" with his team-mate.
After Manchester City's surprise defeat to Norwich City, Pep Guardiola insisted Manchester City's players are responsible for his status.
Luciano Passirani, a pundit on Italian television programme TopCalcio24, has been suspended for making a racist remark about Romelu Lukaku.
AC Milan's Franck Kessie was allegedly racially abused on Sunday but Hellas Verona have released a statement to deny the incident.