Tomas Rosicky fired Arsenal back into the Premier League title race as the Czech midfielder's quick-fire strike clinched a crucial 1-0 win over north London rivals Tottenham on Sunday.
Arsene Wenger's side began the weekend seven points behind Chelsea, but they moved to within four points of the leaders — with a game in hand — thanks to Rosicky's winner after just 72 seconds.
The Czech midfielder's goal, and the gritty defensive display that followed it, secured Arsenal's first league win at White Hart Lane since 2007 in Wenger's 999th match in charge.
The third placed Gunners feared their title challenge was fading after a defeat at Stoke, but they are firmly back in the race and a titanic encounter against Jose Mourinho's Chelsea side looms at Stamford Bridge next weekend.
"It's a huge result because we were under pressure to win before the game," Wenger said. "Tottenham played well and sometimes we were under pressure, so we needed some special resilience to get away with it. It's three massive points."
Tottenham's third successive defeat was harsh on Tim Sherwood's fifth placed team, who look to have blown their chances of qualifying for the Champions League via a top-four finish.
"First and foremost, I wanted the performance. We got that but we didn't get the result," Sherwood said. "The fans won't be happy with that but anyone who has seen that performance will know we didn't deserve to lose."
Arsenal had already defeated their hated neighbours twice this season and they were quickly back in the ascendancy thanks to a virtuoso contribution from the man nicknamed 'the little Mozart'.
Rosicky was only playing because of an injury to the club's record signing Mesut Ozil, but he took less than two minutes to make a more decisive contribution than the German has managed for months.
Rosicky seized possession near the halfway line after a Tottenham attack broke down and surged forward with real intent.
Tottenham were caught short-handed at the back and the Czech picked out Alex Oxlade-Chamberlain on the edge of the penalty area. Oxlade-Chamberlain couldn't control the ball, but it rolled fortuitously back to Rosicky and, although the angle didn't suggest the shot was on, he unleashed a ferocious half-volley that flashed into the top corner past the stunned Hugo Lloris.
It was just Rosicky's third club goal of the season, but Spurs will be sick of the sight of the 33-year-old, who also scored against them in the FA Cup third round.
Rosicky was pulling the strings and he produced a perfectly-weighted pass to put Oxlade-Chamberlain clean through on goal, but the midfielder chipped woefully wide with just Lloris to beat.
Tottenham threatened for the first time when Andros Townsend whipped over a teasing cross that just eluded Emmanuel Adebayor. That provided a much-needed jolt of adrenaline for the hosts, who had made a lethargic start in unseasonably warm temperatures.
The mercury rose even higher when Arsenal right-back Bacary Sagna escaped with only a booking from referee Mike Dean after clattering Danny Rose with a crude lunge.
Tottenham should have been level just after half-time when Arsenal goalkeeper Wojciech Szczesny made a hash of a routine cross. Szczesny tried to catch the ball one-handed but instead fumbled it to Nacer Chadli, yet Arsenal escaped as the Belgian winger shot tamely at Laurent Koscielny with the goal at his mercy.
Sherwood questioned his players' character after their thrashing at Chelsea last weekend, but he could have no complaints here. Spurs were the dominant force and they went close twice in quick succession.
First Chadli flicked wide from Townsend's low delivery, then Adebayor rose highest to meet Nabil Bentaleb's cross but couldn't hit the target with his header.
Sherwood, involved in a row with Benfica boss Jorge Jesus in midweek, has cut a manic figure on the touchline as results have gone against him and he let his emotions get the better of him again when he threw the ball at Sagna in the closing stages.
The hosts kept pressing for an equaliser, but Arsenal, superbly marshalled by Koscielny, threw enough bodies in the way to repel the assault.