Arsenal held on for a pulsating 3-2 North London derby win over Tottenham Hotspur on Sunday after a dreadful error by goalkeeper David Raya allowed their rivals back into a game that had looked out of reach.
Mikel Arteta's side had been coasting after taking a 3-0 first-half lead thanks to an own goal from Pierre-Emile Hojbjerg, a brilliant finish by Bukayo Saka and Kai Havertz's header.
And the Premier League leaders remained in control until a moment of madness from Raya in the 64th minute. Under no pressure, the Spaniard chipped a ball out from the back straight to Cristian Romero who accepted the gift to coolly finish and drag his team back into the match.
Roared on by a home crowd that had been stunned into silence during a dreadful defensive performance in the opening 45 minutes, Spurs were then awarded a penalty three minutes from time.
Arsenal midfielder Declan Rice had fouled Ben Davies in the box and, after being asked by VAR to review the challenge on the pitchside monitor, referee Michael Oliver pointed to the spot and Son Heung-min made no mistake.
But Arsenal managed to hold out and secure all three points to move four points clear at the top of the table.
That lead was reduced to one point when Manchester City won 2-0 at Nottingham Forest later on Sunday and, if they win all of their remaining games, then Pep Guardiola's side, who have a game in hand, will clinch a historic fourth title in a row.
"The last 20 minutes wasn't nice, but it was worth it," Saka, who now has 15 Premier League goals this season, told Sky Sports after the match.
"We know it is a big derby and they don't want to lose 3-0 at home. Momentum shifted their way, but I am proud of the boys – we managed to get the three points.
"We needed to be calm and everything was frantic. We showed our level heads at the end and I am proud of everyone, it was a nice moment – we know what it means to the fans.
"It means everything and it is a massive win for us. We have three to go and we will give it everything."
Arsenal had been given a boost on Saturday when Liverpool could only draw at West Ham United, which left the Merseyside club in third, two points behind the Gunners.
And the Gunners would be in front after 15 minutes at the Tottenham Hotspur Stadium when recalled midfielder Hojbjerg glanced a header into his own net from a Saka corner.
Cristian Romero almost pulled his side level but the Argentine could only crash a header against the post from close range.
Spurs defender Micky van de Ven then saw his cool finish ruled out by a narrow offside call and the home side's frustrations would dramatically increase when Dejan Kulusevski was denied a penalty after colliding with Leandro Trossard.
As the referee waved play on Arsenal launched a devastating counter-attack, with Rice feeding Saka who sent the ball out to Havertz, with the England attacker continuing his run down the right before being picked out in style by the in-form German.
There was still plenty for Saka to do but he showed impressive composure to cut inside Davies before finishing in style low into the net.
And delirious Arsenal fans were celebrating a third goal 11 minutes later when Rice's corner was headed home by Havertz, who had scored twice on Tuesday when his former club Chelsea were blown away 5-0 at the Emirates Stadium.
Another sensational London derby win appeared on the cards for Arsenal until Raya's blunder and Son's penalty made it a nerve-racking final few minutes on enemy territory.
Next up is Bournemouth at the Emirates next Saturday followed by Manchester United away and Everton at home on the final day of the season as the title race heads into the home straight.
"I was praying at the end. It was a really emotional game. This is a tough place to come and a great team to play against. We had to dig in and suffer," said manager Arteta.
For Spurs, it was a second defeat on the spin after their 4-0 thrashing at Newcastle United 14 days ago, which leaves them seven points and one place behind Aston Villa in fourth – although they have two games in hand on Unai Emery's men.
"We allowed them way too easy access to our goal. It's unacceptable at this level and we paid a price for it against a very good team," admitted a frustrated Tottenham manager Ange Postecoglou.
