Substitute Nicklas Bendtner scored with his first touch to ead Arsenal over Tottenham 2-1 in the English Premier League.
|Super sub: Arsenal's Danish Striker Nicklas Bendtner|
The win means Arsenal keeps its eight-year unbeaten streak against its London rival.
Bendtner headed in the winning goal in the 78th minute shortly after the Denmark striker replaced Emmanuel Eboue.
Emmanuel Adebayor had put the Gunners ahead at Emirates Stadium three minutes into the second half, before Dimitar Berbatov leveled in the 66th.
Robbie Keane could have put Tottenham ahead in the 72nd, but his penalty kick was saved by Arsenal goalkeeper Manuel Almunia.
Arsenal extended its lead over second-place Manchester United to four points. United hosts Everton on Sunday.
Tottenham was chasing its first victory over Arsenal since 1999, but Spurs coach Juande Ramos had to contend with an injury crisis for his first north London derby.
The Gunners applied instant pressure on Tottenham's patched-up defence, with Mathieu Flamini volleying wide in the second minute from Adebayor's lofted pass.
Two minutes later, Kolo Toure turned Cesc Fabregas' free kick into Paul Robinson's hands.
Robinson pushed Eboue's shot wide in the 34th as Spurs maintained a solid barrier to offset Arsenal's speed superiority.
At the other end, Tottenham struggled to test Almunia.
Keane returned from suspension to lead the attack alongside Berbatov, forcing Jermain Defoe on to the bench despite scoring in Tuesday's League Cup quarterfinal victory over Manchester City.
William Gallas got a yellow card after a tame tackle on Berbatov in the 38th, but the Bulgarian's weak free kick went into Almunia's hands.
In Tottenham's best breakthrough of the first half, Kevin-Prince Boateng ended Keane and Lennon's neat passing move by producing a curling shot in the 39th which dipped over.
A header from Toure forced Robinson into a reflex save in the 43rd.
Three minutes into the second half, Adebayor got his season-leading 10th league goal.
Tomas Rosicky passed through to Fabregas, who slickly backheeled the ball into the path of Adebayor.
In the 49th, Fabregas came close to doubling the lead.
Keane rattled the crossbar in the 65th with an angled drive from Aaron Lennon's cross.
A minute later, Spurs leveled with a near-replica of Arsenal's opener.
Keane outmuscled Gallas and backheeled to Berbatov, who shot the ball from a tight angle past Almunia.
In the 72nd, Toure fouled Berbatov in the box for a penalty, raising Spurs fans' hopes their team could get its first win at Arsenal since 1993.
But Keane's low drive was blocked by Almunia after the Spanish keeper dived to his right.