Nicklas Bendtner headed the winner seconds after coming on as substitute to keep Arsenal top of the Premier League with a win against Tottenham.
Bendtner turned in Fabregas' corner on 76 minutes
Emmanuel Adebayor put Arsenal ahead after 48 minutes in the north London derby from a Cesc Fabregas back-heel.
Dimitar Berbatov powered home in the 66th minute, then Robbie Keane's penalty was saved by Manuel Almunia after Kolo Toure fouled the Bulgarian.
Substitute Bendtner strode on after 76 minutes and turned in Fabregas' corner.
It was a goal that left Spurs without a victory against their arch-rivals in eight years.
Tottenham boss Juande Ramos sprang a surprise by giving a first start to Jamie O'Hara - and the 21-year-old distinguished himself in a dreadful first half.
Mathieu Flamini hooked wide early on but the visitors were well-disciplined and never allowed Arsenal into their normally smooth stride.
Spurs keeper Paul Robinson saved well from Emmanuel Eboue's shot and Toure's header but there was little sign of the defensive frailties that have plagued Tottenham's season.
The game burst into life three minutes after the re-start when a brilliant flick from Fabregas sent in Adebayor, who slid a composed finish past Robinson.
But Spurs were well in contention and Keane should have equalised after 65 minutes, only to lash a volley against the bar from eight yards when Aaron Lennon's cross found him unmarked at the far post.
Spurs, however, only had to wait a matter of seconds for the equaliser.
Keane produced a neat flick near the byeline and the lurking Berbatov smashed high past Almunia at his near post.
Spurs then wasted a golden opportunity to set the platform for victory after 71 minutes.
Referee Rob Styles rightly pointed to the spot when Toure upended Berbatov but Keane's penalty was too casual and too central, allowing Almunia to dive to his right to save.
And punishment was instant and painful for Tottenham as Arsenal went ahead in remarkable circumstances.
Both managers made changes, with Jermain Defoe replacing the dejected Keane and Bendtner replacing Eboue.
Bendtner had not touched the ball when he made his way into the Tottenham penalty area and rose to power Fabregas' corner past Robinson, once again proving Gunners' boss Wenger has the Midas touch against Spurs.
Arsenal: Almunia, Sagna, Toure, Gallas, Clichy, Eboue (Bendtner 74), Fabregas, Flamini, Rosicky, Hleb (Silva 82), Adebayor.
Subs Not Used: Lehmann, Senderos, Eduardo.
Goals: Adebayor 48, Bendtner 76.
Tottenham: Robinson, Tainio, Chimbonda, Kaboul, Lee (Taarabt 80), Lennon, O'Hara, Boateng (Huddlestone 60), Malbranque, Berbatov, Keane (Defoe 74).
Subs Not Used: Cerny, Archibald-Henville.
Booked: Boateng, Berbatov, Tainio.
Goals: Berbatov 66.
Ref: Rob Styles (Hampshire).
BBC Sport Player Rater man of the match: Arsenal's Emmanuel Adebayor 7.60 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.