Arsenal deceived by Duff the magic striker

Football's version of the Gold Cup took on a new dimension yesterday as the champions' hurdle at Blackburn brought them crashing to earth. The race, which had seemed likely to be decided in Arsenal's favour any weekend now, was declared wide open again as Manchester United's victory at Aston Villa was followed a matter of hours later by Arsenal's first defeat in 20 matches since falling at Old Trafford in early December. The gap between them was therefore reduced to only two points, and United can take the lead for the first time this season by beating Fulham on Saturday morning, a day before Everton visit Highbury.

While Arsène Wenger defiantly maintained that the Double is still on the cards, the double that Lancashire was talking about last night was the one inflicted on his team by a lively and inventive Blackburn this season – the first against Arsenal by any side for three years. Without Andy Cole, who was dropped after falling foul of Graeme Souness at training on Friday morning, the home side fully merited their fourth successive League victory, taking them to seventh in the table.

To compound a bad day, the Londoners also suffered further injury problems ahead of Wednesday's Champions' League match away to Valencia, with Martin Keown now out for three weeks. David Seaman, Sol Campbell and Ashley Cole were all missing yesterday, and it showed. The young goalkeeper Stuart Taylor and Pascal Cygan became ensnared in comical misunderstandings throughout – the first of them five seconds into the game, as Blackburn punted a long ball forward from the kick-off.

Most of the home side's play was more subtle than that and, with Tugay Kerimoglu outstanding, they took advantage of Patrick Vieira's absence to dominate the midfield and leave Souness glowing with satisfaction on the third anniversary of his arrival at Ewood Park. "I was on the touchline feeling quite comfortable, and not many managers can say that against Arsenal," he said. "I felt it would be a good time to play them, but they're a team looking to win the Champions' League and we deserved to beat them."

Wenger could not disagree. "We did not see the real Arsenal," he said. "We did not have the legs and were beaten in too many fifty-fifties. That's an explanation, not an excuse. But it's still in our hands. We have four games left at Highbury and, being strong at home, we'll win the championship."

Souness added that Andy Cole would be disciplined internally, but still had a future at the club: "I fall out with my wife every day but she's still got a future. I don't see it as being a major problem." Cole's absence meant a full debut for the Turkish international Hakan Sukur, who had been in the Galatasaray side who beat Arsenal in the Uefa Cup final three years ago, but broke his leg shortly after arriving at Ewood Park last year. He did little to justify Souness's praise of his industry, but it may have been a calculated jibe at Cole over the need to offer 100 per cent effort in training and matches.

Blackburn were without the midfielders David Dunn – another man to have fallen out with Souness – and David Thompson, but were able to field Damien Duff for the first time in seven games. There was an element of good fortune about his goal in the 22nd minute after a lively start by both sides. Keith Gillespie, who had already troubled the left flank of Arsenal's defence, cut the ball back for Tugay, whose mis-hit drive struck Dwight Yorke and bounced into the air, dropping perfectly for Duff to shoot strongly past Taylor.

The Irishman had made an impact four minutes earlier, tossing the ball stupidly away at an Arsenal free-kick to earn a yellow card. After the ball had been moved forward 10 yards, Giovanni van Bronckhorst drove it fiercely at Brad Friedel as Keown lunged in, just failing to apply the necessary touch and suffering his injury. It was Friedel's second good save of the half, the first having come from a free-kick in Thierry Henry's favourite position, 25 yards out to the left of goal.

Keown's replacement was the midfielder Gilberto Silva, which did not help to tighten up a loose defence, and the home team's half-time lead was well deserved. Duff would have increased it in the 34th minute with another fierce shot, but for Taylor's fine save in the top corner. The closest thing to an equaliser was Robert Pires's weak header from well inside the six-yard box that Vratislav Gresko hacked away after Friedel had, unusually, fumbled a corner.

Errors by Friedel are as rare as goals by Tugay, but there was one of the latter to savour six minutes into the second half. The Turkish midfielder picked up a pass from Duff and drifted from left to right before shooting low into the far corner as Cygan failed to challenge him.

Once Keown went off, the champions had only Lauren of their first-choice back five on the pitch, and it showed. Ray Parlour's vigour in midfield, which earned him a booking for clattering into Gillespie, was no compensation for Vieira's craft, missed all the more because Dennis Bergkamp was not providing any. When he found Henry with a chip from the right, the striker nudged the ball down for Fredrik Ljungberg, whose shot was too high.

Wenger used his two remaining substitutions midway through the second half, with Francis Jeffers and Sylvain Wiltord coming on for Edu and Pires, but there was only minor improvement, and Ljungberg's earlier effort remained their only threat of the second half.

Now the race is on again between the Premiership's two thoroughbreds, and suddenly United look the fresher.

Blackburn Rovers 2 Arsenal 0
Duff 22, Tugay 52

Half-time: 1-0 Attendance: 29,840