Arsenal beat London rivals Chelsea 3-1 for their first league win in nearly two months as goals from Alexandre Lacazette, Granit Xhaka and Bukayo Saka lifted the pressure on coach Mikel Arteta.
Arsenal, missing several first-choice players, took the lead in the 35th minute when Lacazette sent Chelsea goalkeeper Edouard Mendy the wrong way from the spot after Kieran Tierney was adjudged to have been clipped in the box by Reece James.
Nine minutes later, Xhaka lifted an unstoppable free kick over the wall and beyond Mendy's dive.
A visibly frustrated Chelsea coach Frank Lampard tried to turn the tide at half-time when he replaced out-of-form Germany striker Timo Werner with winger Callum Hudson-Odoi and Mateo Kovacic with Jorginho.
But Chelsea were only marginally more threatening for most of the second half and Arsenal sealed the win in the 56th minute when Saka floated what looked like a cross over Mendy and the ball hit the far post and went in.
Chelsea snatched a consolation goal with five minutes to go when Tammy Abraham converted a cross by Hudson-Odoi.
Jorginho could have set up a tense finale but his poorly taken penalty was saved by Bernd Leno.
"It's a really important win for us. Some of the performances haven't been enough to win football matches and that is something difficult to handle over time," Arteta said.
"We needed points and today we have done it in a really convincing way," he said. "It's been some difficult weeks."
Arsenal had failed to win any of their previous seven league games -- losing five of them -- and the win lifted them to 14th place in the table. Chelsea are sixth after their third consecutive away defeat.
The Gunners went into the game with talk of a relegation battle swirling around the Emirates Stadium after their worst showing in the league so far in nearly 50 years.
To compound their problems, they were missing David Luiz and former Chelsea midfielder Willian, who felt unwell. Both were left out as a precaution despite testing negative for the coronavirus.
Brazilian Gabriel was sidelined after being in contact with someone who tested positive for COVID-19 and out-of-form striker Pierre-Emerick Aubameyang was on the bench after an injury worry.
But Arsenal looked hungry for a win right from the kickoff and understudies Emile Smith Rowe and Gabriel Martinelli, back from injury, threatened Chelsea with their pace.
Lampard was left to lament Chelsea's slow start.
"Didn't do enough first half, better second half but we had too much to do at that point," he told reporters. "All the basics were wrong."