Arsenal needed victory to replace Liverpool at the top but lost 2-0 to West Ham on a night where David Moyes finally landed a victory at the Emirates Stadium.
His side lost Kurt Zouma ahead of the game and Lucas Paqueta after just over half an hour but hit the front through Tomas Soucek’s strike, awarded after VAR could not determine whether the whole ball had gone out of play in the build-up.
A second-half header from former Arsenal defender Konstantinos Mavropanos secured the points and things could have been even better for the visitors had Said Benrahma not seen a last-gasp penalty saved by David Raya.
Moyes had failed to secure victory in his previous 72 Premier League away games at Arsenal, Chelsea, Liverpool or Manchester United, so this was a long time coming for the Scot.
The Gunners laboured when they needed to continue their recent winning run in London derbies to go back to the top of the table.
Instead, only captain Martin Odegaard could hold his head high on a night where their defence creaked and Gabriel Jesus was guilty of missing a couple of very good chances.
Arsenal started well, with some great touches in and around the West Ham box from Odegaard in particular.
But at the other end their defending left a lot to be desired, as Oleksandr Zinchenko and Gabriel Magalhaes failed to deal with a simple ball into the middle.
Jarrod Bowen took advantage by latching onto the miscue and teed up Soucek to finish – the goal surviving a lengthy VAR check which could not ultimately make a call on if the ball had not gone out of play before Bowen’s cutback.
Arsenal looked to respond although the goal gave West Ham something to defend, although Jesus found a way in behind with a subtle flick into Bukayo Saka, whose header was brilliantly saved by Alphonse Areola.
Paqueta had been hurt in the warm-up and lasted just over half an hour, with his fellow Brazilian Gabriel Martinelli curling an effort just wide for Arsenal as they continued in vain to find a leveller.
The hosts were getting closer, West Ham gifting possession as two passes saw Arsenal in on goal once more, this time Saka hitting the base of the post from an acute angle.
Former West Ham captain Declan Rice fired just over from 25 yards but it was another player coming back to haunt his former club who would find the back of the net soon after.
Mavropanos made just seven league starts in three years as an Arsenal player but returned to the Premier League last summer with the Hammers and headed them two goals ahead before the hour.
Jesus then headed straight at Areola before sending another fine chance well over the bar moments after Arteta introduced Eddie Nketiah and Reiss Nelson off the bench.
Areola was on hand again to keep out a Leandro Trossard effort, with Vladimir Coufal clearing a William Saliba header off the line from the resulting corner.
Rice had come off the bench during a 3-0 Carabao Cup defeat on his return to West Ham earlier in the season and endured another night to forget here as he conceded a late penalty for tripping Emerson Palmieri in the box – only for Raya to keep out substitute Benrahma’s tame spot-kick.
