Tottenham Hotspur dealt a potentially fatal blow to north London rivals Arsenal's Premier League title hopes with a 2-1 win at White Hart Lane on Wednesday.
A superb Danny Rose volley and a second from Gareth Bale edged Nicklas Bendtner's second half effort to hand Spurs a first league win over Arsene Wenger's side in 11 years.
The defeat leaves third-placed Arsenal six points behind leaders Chelsea with four games remaining. Spurs stay fifth on 61 points, one behind Manchester City after 33 matches.
Wenger conceded his team's title prospects were now remote but refused to give up the fight.
"As long as it's mathematically not impossible you can not say impossible," he told Sky Sports. "Our job is to fight and we will do that."
Spurs manager Harry Rednapp added: "It's about 11 years since we beat Arsenal so it was a great result for us. Sunday's (FA Cup semi-final defeat) knocked us all for six to be honest, but we showed the character we've got at the club."
Elsewhere, seventh-placed Aston Villa salvaged a late 2-2 draw against Everton, who are in eighth spot. Tim Cahill headed in both Everton's goals either side of Gabriel Agbonlahor's second-half header before Phil Jagielka's injury-time own goal levelled it.
At the bottom of the table, relegation-threatened Wigan Athletic were held 0-0 at home by already condemned Portsmouth to leave them five points clear of the drop zone in 16th place.
Wenger sent his side into the London derby with a must-win message if they were to secure a first league title since 2004 but their strong start was halted by a stunning Rose strike.
The 19-year-old midfielder made sure his first Premier League start was one to remember when he met Arsenal goalkeeper's Manuel Almunia's punched clearance with a crashing 30 metre volley which rocketed in on 10 minutes.
"He is a good little player. That was great technique and a great goal," Redknapp added.
It got worse for Arsenal soon after when key defender Thomas Vermaelen limped off injured and despite dominating possession Wenger's side had no answer to Tottenham's resilience.
Immediately after the restart, Gareth Bale was left unmarked and onside to calmly slot a second for the hosts. Boosted by the late introduction of Theo Walcott and Dutchman Robin van Persie, back after a five-month injury absence, Arsenal began to rally.
Danish striker Nicklas Bendtner slid home on 85 minutes and defender Sol Campbell, who had an effort cleared off the line in the first half, had a late header tipped onto the bar against his old club.
Spurs, with Ledley King back in defence after seven weeks out injured, nullified Arsenal for long periods with a strong defensive display and are now firmly in the race for the fourth Champions League qualifying place.
Aston Villa's push for that very same position continued to falter with their draw against a resurgent Everton side now unbeaten in seven league matches.