Arsenal were able to weather a grandstand finish to move a step closer to a first Premier League title in 20 years with a potentially season-defining 3-2 victory at rivals Tottenham.
The Gunners held a one-point lead over Manchester City ahead of Sunday's clash but all eyes were on whether Mikel Arteta's men could pass this latest stern test and they did to remain at the summit going into May.
A Pierre-Emile Hojbjerg own goal gave Arsenal the perfect start after 15 minutes and not long after Micky van de Ven had seen an effort ruled out for offside, Bukayo Saka made it 2-0.
Saka's classy 27th-minute finish after a slick counter-attack put the visitors in cruise control and when Kai Havertz continued his great form with a 13th goal of the season from another set-piece, the Gunners were in dreamland.
Tottenham produced a stirring second-half response, albeit after being given a helping hand by their bitter rivals after goalkeeper David Raya chipped straight to Cristian Romero, who reduced the deficit with 26 minutes left.
When Declan Rice fouled Ben Davies inside the area and Heung-min Son fired home with three minutes left it set up a dramatic finale, but Arsenal held on to claim a crucial win from their 35th league match of the season.
This was arguably the biggest north London derby since Arsenal won the league at White Hart Lane in 2004 and the visitors went into the game on the back of a thumping 5-0 win against Chelsea.
A white-hot atmosphere greeted the Gunners, which they briefly silenced when Havertz fired home after 13 minutes, but it was ruled out for offside.
It had been an even start and yet Arsenal claimed the decisive opener two minutes later.
Saka's corner to the near post was headed into his own net by the recalled Hojbjerg, who had been battling with Takehiro Tomiyasu.
Tottenham responded with Romero nodding wide from a James Maddison corner before the same duo combined shortly afterwards, but Romero could only crash his header against a post.
Spurs continued to be in the ascendancy and thought they had equalised in the 22nd minute.
Pedro Porro's deflected effort ballooned into the path of Van de Ven, who smashed the ball past David Raya, but home celebrations were cut short when the Dutch defender was adjudged to be fractionally offside by VAR Jarred Gillett.
Tottenham's next attack ended with Dejan Kulusevski going down in the area after the slightest contact by Leandro Trossard, but referee Michael Oliver waved play on and Arsenal produced a devastating counter-attack.
Havertz spotted Saka in space on the right and found the England international, who cut inside Davies and curled the ball into the bottom corner for his 19th goal of the season.
Spurs' players remonstrated with Oliver before Timo Werner was forced off with an injury, but things went from bad to worse in the 38th minute.
Another set-piece proved Tottenham's undoing as an inswinging corner by Rice on top of Guglielmo Vicario was headed in from close range by Havertz.
Son fired over before a disastrous first half for Spurs came to an end and while Romero headed another decent chance off target at the start of the second period, it was nearly 4-0 in the 53rd minute.
Havertz got in behind the home defence and teed up Saka, but his volley was brilliantly kicked over the crossbar by Vicario.
Just as a sense of flatness was slipping back into the Tottenham crowd, Arsenal gifted them a lifeline.
Romero was rewarded for being the one-man press when Raya inexplicably chipped the ball straight to the Spurs centre-back, who side-footed into the corner.
Spurs boss Ange Postecoglou had sent on Yves Bissouma and Richarlison by this point, but the visitors appeared to have weathered the storm before a dramatic finale ensued.
Davies beat Rice to a loose ball in the Arsenal penalty area and after VAR told referee Oliver to review the incident, he pointed to the spot.
Son drilled past Raya with three minutes left but the hosts could not muster an equaliser despite a flurry of stoppage-time set-pieces as the Gunners came through to claim a victory which also secures 'St Totteringham's Day' – the point when Tottenham can no longer finish above their rivals.
However, Arsenal have greater targets in mind with the title race set to go to the wire.