Charlton 1 Arsenal 0
Arsenal's title hopes suffered a potentially fatal blow as they crashed to defeat at London rivals Charlton.
Already eight points behind leaders Manchester United at the start of play, the Gunners could ill afford another slip-up after blowing a two-goal lead at home to Sunderland on Saturday.
But Jonatan Johansson's 13th goal of the season on 38 minutes was enough for the Addicks with Dean Kiely securing the three points with a brilliant save from Nelson Vivas' 75th-minute penalty.
And Sir Alex Ferguson's side can now stretch their cushion at the top of the Premiership to 11 points with victory over West Ham at Old Trafford tonight.
Charlton boss Alan Curbishley unsurprisingly kept faith with the side that ended an awful away run at Manchester City on Saturday for the visit of Arsenal.
But there was no such luxury for Gunners boss Arsene Wenger, who was without the services of nine first team players at The Valley.
Top-scorer Thierry Henry, ruled out with an ankle injury picked up against Sunderland, was the latest addition to a lengthy casualty list including the likes of Tony Adams, Martin Keown, Dennis Bergkamp, Sylvain Wiltord and David Seaman.
That meant a very unfamiliar Arsenal line-up with Gilles Grimandi alongside Igor Stepanovs at centre-half, Nelson Vivas getting a rare start in midfield and Fredrik Ljungberg pushed up front alongside Kanu.
It was no surprise therefore that the visitors struggled to establish the attacking fluency that ripped apart Sunderland in the first half on Saturday although they did enjoy the better of the opening period.
Kanu turned Scott Parker inside out but dragged his left foot shot well wide after five minutes before Silvinho curled a 12th-minute free-kick just wide of Dean Kiely's left-hand post.
Arsenal looked more like the home side as they forced Charlton back time and again and made light of the unusual formation and personnel.
Vieira, who was sent off on his last appearance at The Valley two years ago, just failed to get a touch to Silvinho's inswinging free kick and Parlour, booked for a foul on Parker, brought a fine save from Kiely with a right foot drive from 25 yards out.
Kiely also smothered a left foot shot from Ljungberg from distance and the Arsenal fans must have felt it was only a matter of time before their team's dominance was rewarded.
But as against Sunderland on Saturday, the Gunners failed to make the most of their total dominance and were severely punished on 38 minutes.
That was how long it took for Charlton to muster their first genuine attack of the game, and from it they scored.
Graham Stuart simply hooked the ball across the area and when it just cleared Stepanovs, Jonatan Johansson climbed above Silvinho to head past Manninger from seven yards out.
Arsene Wenger looked stunned on the touchline and his mood was not improved when Vieira blazed over from 10 yards out with the last touch of the first half.
After creating just two noteworthy chances in the first half Charlton then had three opportunities to double their lead in a frantic opening to the second period.
Arsenal failed to clear Jensen's initial corner and when Stuart curled the ball back to the far post Manninger only just got there ahead of Rufus to turn the ball round of the upright.
From the resulting corner Manninger was more convincing as he turned over Todd's near post header and the Austrian goalkeeper again did well seconds later when Bartlett was left unmarked in the area from Jensen's cross, palming away the South African international's header at his near post.
At the other end Arsenal's opportunities were far more limited but Ljungberg should have done better when presented with the ball 12 yards out from Parlour's pass, the Swede failing to connect properly with his shot and Kiely gratefully gathered.
Johansson glanced a header over the bar before the home side missed a glorious chance to double their lead on 58 minutes. The tireless Jensen got to the byline and pulled the ball back for Bartlett who seemed to have the goal at his mercy, only for the striker to lose his balance and completely miss the ball to allow Grimandi to clear.
Wenger brought on Ashley Cole and Tomas for Silvinho and Pires, the latter joining Ljungberg and Kanu up front, but it was Charlton who again went close to a second, Stuart curling a 20-yard effort just wide of the upright.
Arsenal were handed a lifeline a quarter of an hour from time when Fish was adjudged to have brought down Tomas in the area and referee Graham Poll pointed to the spot despite the Charlton protests.
But Kiely brought the home crowd to their feet with a brilliant save, diving away to his left to get his left hand to Vivas' spot kick and turn the ball away for a corner.
That just about summed up Arsenal's afternoon and although they threw everything forward in the dying minutes Charlton held on for the win that could signal the end of the title race.