BRIAN Laws had left Ewood last night when Burnley's derby preparations received an unexpected boost. He departed knowing Sunday's main task would be stopping David Dunn, yet Barry Ferguson may have done the job for him.

If anyone had forgotten just what Dunn was capable of, after a period of injuries and mixed performances, they were reminded during Blackburn Rovers’ 2-1 win over Birmingham City.

If ever there was a 90 minutes that encapsulated Dunn’s career, it was this one.

There was talismanic attacking drive and goals from midfield, even arguments. Then, just when things were going so well, there was injury.

The scorer of both goals, Dunn was superb - head and shoulders above every other player on the field. Chants of ‘Dunny for England’ began to resurface.

There was brief concern when he left the field at half time in heated dispute with team-mate Michel Salgado over defensive responsibilities, and Sam Allardyce later revealed that the argument briefly developed into a dressing room scuffle.

But that appeared to be forgotten by the time the second half came around and Dunn went on to complete arguably his best performance since his role in derby victories over Burnley and Bolton in the autumn.

Most around the ground sensed a man ready to unleash his top form on Burnley once more.

A lifelong Rovers fan, no player out there on Sunday can claim a greater passion for the fixture.

Yet there was always a fear he had peaked too soon and, even if it was not of his own doing, that fear may have been realised.

There were only minutes remaining when Dunn was kicked up in the air by Stephen Carr. As he hobbled around attempting to recover, he was kicked up in the air again by Ferguson.

Think Claudio Caniggia against Cameroon at Italia ’90 (available on YouTube for those who need their memories jogging) with a slightly greater time lapse in between challenges.

Ferguson was not exactly popular around Ewood in any case, particularly after insisting this week that he was not a Blackburn Rovers flop during his time with the club.

"I think if you asked Blackburn fans then they would agree," said Ferguson.

Bad news for you, Barry. We’ve asked them and they don’t seem to.

Allardyce was furious afterwards with both Ferguson and referee Mark Clattenburg for allowing the challenge to pass without a card.

Rovers will wait to assess Dunn’s fitness, but the initial indications did not sound promising.

Allardyce spoke of taking no chances with his injury-prone midfielder, while acknowledging that Dunn would want to play on Sunday.

The Rovers boss even bravely used the term 'rest', for what is arguably the most important fixture of the season in the eyes of Blackburn fans, when musing over a possible bench role for Dunn.

Yet Dunn was the difference when Rovers beat Burnley 3-2 at Ewood in October and Laws – at Ewood last night along with backroom staff Russ Wilcox and Stuart Gray before leaving 10 minutes early, as is the convention – could only have been impressed.

The midfielder has long been the focus of the Burnley faithful’s antipathy, as demonstrated by a rather bizarre threat to paint his house claret and blue before this derby.

Such attempts to unsettle the 30-year-old only serve to illustrate how important he is to Rovers.

On last night's form, Burnley could receive no greater boost than to pick up the teamsheet on Sunday and see Dunn’s name absent.