Jose Mourinho was critical of Manchester United's loss at West Ham, but Ole Gunnar Solskjaer did not bite back at his predecessor.
Manchester United's problems on the road continued with a 2-0 defeat at West Ham, while leaders Liverpool made it six wins out of six.
Half of the Premier League's 'big six' all lost at the weekend, with Liverpool and Manchester City showing they are way ahead of the rest.
Liverpool survived a late fightback to earn a 2-1 win at Chelsea, after which Jurgen Klopp admitted Manchester City make winning look easy.
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.