Blackburn 2-0 Arsenal
Arsenal finally displayed signs of feeling the pressure at the top of the Premiership as Blackburn forced a deserved win at Ewood Park.
Damien Duff celebrated his return from a six-week injury lay-off with a first-half opener and Tugay sealed victory with a 52nd-minute strike as the Gunners failed to respond to Manchester United's lunchtime victory over Aston Villa.
The defeat was Arsenal's first since their 2-0 reverse at Old Trafford on 7 December and leaves the Gunners just two points clear of Manchester United.
And, to make matters worse, Arsene Wenger saw his side's injury crisis deepen on the eve of a crucial Champions League trip to Valencia.
Already without David Seaman, Sol Campbell and Ashley Cole through injury, Arsenal lost Martin Keown to a hamstring strain as the experienced centre-back stretched to help on Giovanni van Bronckhorst's free-kick midway through the first half.
Midfielder Gilberto Silva stepped off the bench as an emergency defender, leaving Lauren as the only first-choice player in the back five.
The makeshift rearguard was given an instant examination by hungry Blackburn.
Keith Gillespie was enjoying himself against stand-in left-back Van Bronckhorst and it was his run and cross which set up the opening goal.
Duff, back in the side after a six-week injury lay-off, scuffed his first effort, but when Tugay's shot was blocked Duff made no mistake with his second attempt.
19 mins: Keown limps off with a hamstring strain
22 mins: Duff fires Blackburn in front
52 mins: Tugay drills home Blackburn's second
Duff might have had a second when his rising shot was superbly saved by Stuart Taylor and the confusion at the back for Arsenal was summed up when Pascal Cygan hacked the ball out of his own keeper's reach to concede a cheap corner.
Arsenal struggled to offer their usual cutting edge but should have been on level terms before half time when Van Bronckhorst's corner found Robert Pires three yards out, only for the French midfielder to loop a header up and over the bar.
But their uphill task became a mountainous one seven minutes into the second half when Tugay fired home from the edge of the box.
Duff broke from the halfway line and fed Tugay, who cashed in on Cygan's hesitancy to drive wide of the unsighted Taylor.
The goal was enough to end Arsenal's 20-match unbeaten league and cup run and the champions rarely looked like repairing the damage.
Rovers shut up shop superbly in the second half to complete a double of their own against the Double winners.
Graeme Souness's side have now won both Premiership games against Arsenal this season and Rovers' victory takes them to within two points of the Premiership's guaranteed European places.
Blackburn: Friedel, Taylor, Berg, Short, Gresko, Gillespie,
Flitcroft, Tugay, Duff (Johansson 69), Sukur,
Yorke (Gallagher 78).
Subs Not Used: Grabbi, Douglas, Kelly.
Booked: Duff, Tugay, Flitcroft, Sukur.
Arsenal: Taylor, Lauren, Keown (Silva 18), Cygan,
van Bronckhorst, Pires (Wiltord 69), Parlour, Edu (Jeffers 69),
Ljungberg, Bergkamp, Henry.
Subs Not Used: Toure, Warmuz.
Booked: Parlour, van Bronckhorst.
Referee: S Bennett (Kent).