Defensive errors cost the Gunners as they gave away an early lead and lost 2-1 at Tottenham in the north London derby.
Arsenal will be kicking themselves all the way back down the Seven Sisters Road.
This was a north London derby they should have won comfortably, but familiar frailties at the back meant they instead left Tottenham empty handed after a 2-1 defeat.
It is a defeat that leaves them ninth in the Premier League, two points behind their neighbours with just three games remaining and on the verge of missing out on European qualification for the first time in 25 years.
It was also a defeat all of their own making.
Having gone in front in the first half thanks to Alexandre Lacazette’s stunning strike from distance, they gifted Spurs an equaliser moments later when Sead Kolasinac misplaced a back pass and allowed Son Heung-min to race clear and score.
And then having dominated the majority of the second half and seen Pierre-Emerick Aubameyang rattle the crossbar, more slack defending saw Toby Alderweireld head home the winner from a corner with nine minutes remaining.
It was a hammer blow for Arsenal in their attempt to land a Europa League spot for next season, and a clear sign to Arteta that even though things have improved defensively in recent weeks, there is still a lot of work to be done – both on the training field and in the transfer market.
Since the Spaniard arrived in December, Arsenal have now dropped 15 points from winning positions – more than any other side in the Premier League.
Nine of the 17 goals they have conceded under Arteta have also come in the 75th minute or beyond, which is a perhaps a sign that the intensity that he is demanding from his players is taking its toll late on.
There is no doubt Arsenal are improving under Arteta and heading in the right direction, but until they cut out the errors at the back they will be unable to challenge towards the top of the Premier League.