|Match winner: Tuncay Sanli (r) becomes an instant local hero in Middlesbrough [AFP]|
Arsenal lost their first game of the season and saw their lead in the English Premiership League slashed to a solitary point, after a spirited Middlesbrough outfit upset Arsene Wenger's side 2-1 on Teeside.
Goals from local product Stewart Downing and Turkish international Tuncay Sanli gave the home side their first win in any competition since September 1 much to the relief of manager Gareth Southgate.
Czech midfielder Tomas Rosicky scored an injury-time consolation goal for Arsenal.
In other results, Bolton beat Wigan 4-1 for their biggest win this season, Tottenham defeated Manchester City 2-1 with a late goal from Jermain Defoe, and West Ham beat host Blackburn 1-0.
After 15 matches Arsenal still lead the league with 37 points, followed by Manchester United with 36 and Chelsea with 34.
"We lost the game because we deserved to lose it," Arsenal manager Arsene Wenger said.
"It's that simple. Middlesbrough were sharper in the fight."
Middlesbrough scored in the fourth minute with a penalty kick from Downing, who sent Arsenal goalkeeper Manuel Almunia the wrong way.
The spot kick was awarded after Arsenal defender Kolo Toure brought down former teammate Jeremie Aliadiere in the penalty box.
The young Frenchman had used his famed speed to burn past Toure and force the Ivorian into a rash challenge.
In the 74th, 'Boro had a deserved second goal when Sanli scored into the corner with a rebound after Almunia had pushed away a shot from Middlesbrough midfielder Gary O'Neil.
In injury time Rosicky turned in a cross from Gael Clichy in injury time, which maintained the Gunners record of having scored a goal in every Premier League match this season.
Middlesbrough's physical approach prompted Wenger to replace Eduardo da Silva with the taller Nicklas Bendtner at halftime, and Theo Walcott and Denilson with 30 minutes remaining, but the Gunners still struggled.
"Our approach to [the game] was fantastic," Southgate said.
"I felt Arsenal having three games in a week was a tall order for them and thought it might be a good day to get them."
The calendar does not look any clearer for Arsenal, which drew 1-1 with Newcastle four days ago, as they now face Steaua Bucharest in the Champions League on Wednesday.
Arsenal had been the only unbeaten club in the Premier League after Liverpool lost to Reading 3-1 on Saturday.
Bolton's revival continues
Bolton took the lead with an own-goal from Wigan defender Paul Scharner in the fourth minute.
|Bolton buoyant: Nicolas Anelka (r) and Kevin |
Nolan celebrate [AFP]
Denny Landzaat equalised for Wigan in the 14th.
Nicolas Anelka missed a penalty kick in the 23rd minute, sending it over the bar.
But he helped set up Kevin Nolan to put Bolton ahead in the 37th.
Kevin Davies scored from a free kick from El Hadji Diouf in the 70th and Anelka wrapped up the win in the 89th.
Tottenham won its third game this season when Defoe scored with a rebound in the 83rd minute after Steed Malbranque's shot had hit the post.
A minute before, Manchester City midfielder Stephen Ireland was sent off for a challenge on Lee Young-pyo.
Tottenham went ahead in the 44th with a close-range goal from Pascal Chimbonda.
Rolando Bianchi levelled in the 61st by heading in a corner from Martin Petrov.
Ashton's happy returns
Dean Ashton, who had come on as a substitute at halftime, scored for West Ham in the 52nd after George McCartney had cut the ball back to him.
West Ham goalkeeper Robert Green preserved the win by saving a shot from Tugay Kerimoglu at close range in the 88th.