Arsenal overcame the hurdle of a north London derby and an anxious finale to maintain momentum in the Premier League title pursuit with a vital victory at Tottenham.
Mikel Arteta's side moved four points clear at the top of the Premier League, with second-place Manchester City, who have two games in hand, playing in the later kick-off at Nottingham Forest (16:30 BST).
The Gunners' meeting with their bitter rivals was seen as arguably the most treacherous of their remaining fixtures, but they took ruthless advantage of Spurs' defensive flaws to establish a three-goal lead by half-time.
Arsenal were then thrown off course when a dreadful clearance by goalkeeper David Raya presented Cristian Romero with a goal after 64 minutes, the nerves really jangling when Heung-min Son scored from the spot three minutes from the end of normal time after Declan Rice fouled Ben Davies.
It was all so different when Arsenal went ahead after 15 minutes as the recalled Pierre-Emile Hojbjerg glanced Bukayo Saka's corner into his own net, the England forward crowning a sweeping counter-attack with a smooth finish for the second after 27 minutes.
Spurs, who saw Micky van de Ven's goal ruled out for a marginal offside with the score 1-0, were infuriated as they claimed Leandro Trossard had fouled Dejan Kulusevski before Saka scored, and were even more frustrated when the unmarked Kai Havertz headed in Arsenal's third from another corner seven minutes before the break.
Arsenal were then content to see out the victory, only for Raya to give Spurs hope by sending a clearance straight to Romero.
An unlikely comeback seemed on when Son scored from the spot but Arteta's side were able to close out the game, denting their arch-rivals' hopes of a top-four finish.
Spurs remain in fifth place in the Premier League, seven points behind Aston Villa with two games in hand.
The Gunners were never actually near their best but when the season reaches this point it is about winning and the job was eventually done, but not without a nail-biting finish.
Arsenal were sitting pretty at half-time and had negotiated the first 20 minutes of the second half without incident until Raya appeared to be caught in a moment of indecision as he went to clear, passing the ball straight to a grateful Romero.
And when Son scored from the spot Arteta's side must have feared becoming the victim of a smash-and-grab as Spurs, a threat going forward throughout, sensed they may get a draw.
In Raya's defence, he did well after his error as he commanded his area with safe handling to ensure the cushion provided by that first-half advantage proved enough.
Arsenal had another stellar performer in Rice, his mistimed tackle on Davies that resulted in a penalty a rare blemish on an otherwise top-class performance.
Arteta's side have put together three wins in eight days to ensure they are right in this title fight with three games left, maintaining pressure on Manchester City as Liverpool's challenge falls away.
Tottenham Hotspur felt the pain of a derby defeat and a setback to their hopes of a top-four finish in the Premier League as they were undone again by vulnerability at set-pieces, in this case corners.
Spurs will be unhappy at Arsenal defender Ben White's distraction of keeper Guglielmo Vicario at corners but they simply had to do better as Hojbjerg headed into his own net early on, the Denmark midfielder stretching to get in front of Takehiro Tomiyasu and glancing the ball in.
Then Havertz rose virtually unaccompanied to head in at the near post for the third, and eventually decisive, goal for the away side.
The frustration for manager Ange Postecoglou is that his side were a genuine source of danger going forward, with what would have been an equaliser for Van de Ven ruled out by the thinnest of margins at a crucial stage.
And they had Arsenal on the rack once they got the scent that something might be in this for them, but in the end the mountain they created for themselves by conceding those three first-half goals proved insurmountable.
