Blackburn 1 Arsenal  1:Somebody must have forgotten to tell Jens Lehmann that Blackburn and Arsenal tend to exchange abuse not presents. After looking set to collect three points from a fractious encounter in which seven players were booked and Ryan Nelsen dismissed, the Arsenal goalkeeper committed his second embarrassing mistake of the season and presented David Dunn with an equaliser. Arsene Wenger will not admit it but the German is becoming a liability.

There seemed little danger when Dunn picked up possession midway inside the visitors' half but, after swapping passes with Matt Derbyshire, he struck a 25-yard shot that Lehmann ought to have held comfortably. But the ball squirmed from his hands and over the line. Last week he botched a back pass and Fulham scored.

Lehmann again stood humiliated. His time-wasting had already antagonised the Rovers fans, tactics that ensured his faux pas was greeted with delight.

"We conceded a bad goal," Wenger said. "Of course (Jens) is really unhappy with it. He's really down in the dressingroom because I don't need to tell him that he made a mistake. We don't want to blame him today."

Meetings between Blackburn and Arsenal have become synonymous with ill-discipline in recent times - eight players have been sent off during Premier League matches involving the clubs - and this fixture continued the trend.

Wenger described Blackburn as "over-physical" and also claimed: "I think sometimes there was a desire of violence rather than commitment in some challenges."

Mark Hughes, predictably, reacted angrily to those remarks. "That attitude doesn't surprise me," said the Rovers manager. "It was a cheap shot. He was hiding behind those comments because his team were dominated over 90 minutes. I don't think he was very gracious. On occasions managers of the top teams have to hide behind the criticism of the opposition when they have not got the result they thought they deserved."

Hughes also pointed to Robin van Persie's foul on Nelsen in the 74th minute, when the Dutchman caught the Blackburn defender late and left him in a heap on the touchline. "The worst challenge (of the game) was Van Persie's," he claimed. "I saw the lad (Dave) Kitson get sent off (against Manchester United) and it was exactly the same challenge."

Van Persie escaped with a yellow card but Nelsen was not so fortunate and was sent off 10 minutes later. The Blackburn defender had already been cautioned when he hauled down the Dutchman as the forward burst on to Nicklas Bendtner's flick-on and the referee's decision was routine.

Arsenal were already a goal to the good by then, Van Persie taking his tally against Rovers to seven in six matches when he slotted from six yards.

Blackburn will lament the concession, particularly Nelsen who failed to head clear before Brad Friedel smothered at Eduardo da Silva's feet.

Dunn, indefatigable in Rovers' midfield, blocked as Cesc Fabregas waited to pounce but the loose ball ran invitingly for Van Persie to convert.

The breakthrough galvanised Arsenal, with their only moments of consternation in the first half coming when William Gallas hobbled off - Wenger revealed the Frenchman has suffered a groin injury and will be sidelined for three weeks.

Three minutes later Blackburn were denied a penalty when the referee deemed Lehmann had been impeded seconds before Fabregas handled Christopher Samba's shot on the line.

Arsenal might have got through it but Lehmann, having just tipped over Morten Gamst Pedersen's free-kick, produced his gaffe.

There was, however, still time for Dunn to block at Denilson's feet, Nelsen to pick up that second yellow and Bendtner to drill wide from 12 yards.