Goals from Clinton Morrison, Stephen Clemence, Mikael Forssell and Bryan Hughes helped Blues wipe out the memory of the 4-0 defeat on the same ground last month.

But it came at a price as Matthew Upson, Stan Lazaridis and David Dunn all had to be substituted through injury.

Blues manager Steve Bruce had described the previous encounter with Blackburn as the low point of his two years at St Andrews and his side, who had fallen at the third round hurdle the previous three seasons, were fired up from the first whistle.

Dunn was in sparkling form against his former club before he limped out of action midway through the second half.

Robbie Savage and Damien Johnson also had a grip on proceedings in the midfield while Kenny Cunningham held together a back four forced into a reshuffle after the injuries to Upson and Lazaridis.

There were further signs that the Morrison-Forssell partnership, which had flourished at Crystal Palace two years ago, was beginning to gel.

After two floodlight failures, referee Paul Durkin finally allowed the match to get underway 35 minutes late.

Dunn was determined to prove a point against his former team-mates as the home side quickly took command of proceedings.

Morrison’s early header from Savage’s corner flashed just wide and Andy Todd came to Blackburn’s rescue when he headed a curling shot from the Wales international off the line.

Andy Cole was looking sharp and one run saw him evade the challenges of Savage and Cunningham only for Maik Taylor to block his low drive.

Dunn stung the fingers of Friedel with a rising shot from 25 yards out after cutting in from the left flank was Hughes was only inches wide with a curling shot after Forssell had laid the ball into his path.

But Hughes was not to be denied and after 22 minutes he set up the opening goal for Morrison. The Republic of Ireland striker took a pass from Hughes into his stride after a mistake by Craig Short, steadied himself before side-footing past Friedel.

Birmingham were sharper in all departments and Forssell drilled a low shot past the dive of Friedel but inches wide of the far post after Savage had created the opportunity.

It was no surprise when Steve Bruce’s side doubled their lead after 34 minutes with Dunn the creator.

He made a surging run into the Blackburn penalty area before crossing into the path of Forssell. He was unable to get a shot in but had the presence of mind to hold the ball up and find Stephen Clemence, who slotted his shot into the corner of the net.

Blackburn manager Graeme Souness opted for a half-time substitution, sending on Dino Baggio for Alan Mahon.

Baggio, on loan for the season from Lazio, almost made an instant impact with a stinging 20 yard shot which flew inches over Maik Taylor’s crossbar.

But the woodwork denied Forssell from putting Blues further ahead after 54 minutes after Dunn had been the creator.

It was the turn of the crossbar to deny Baggio a goal after Taylor had got his fingertips to a rasping drive.

Dunn appeared to be suffering from an injury and was restricted in his movements but he was kept on the pitch by Steve Bruce.

A miskick by Friedel flew straight to Morrison but, instead of trying to find Forssell, he opted to shoot and was well off target.

Friedel than appeared to lose sight of swerving shot from Forssell before parrying around the post at the last minute.

But the Finland international got on the scoresheet with 12 minutes left after being played onside by Martin Taylor – his ninth goal in 14 starts.

Then with seven minutes left Hughes had all the time in the world to drill a low shot past Friedel, with Forssell the creator.