Wenger, typically, handed opportunities to a whole team of young fringe players and his bold selection reaped rich rewards again when Abou Diaby and Eduardo put the Gunners 2-0 ahead after 29 minutes.

Blackburn striker Roque Santa Cruz, a £3.6million summer recruit from Bayern Munich, pulled a goal back three minutes before the break and then headed his 11th of the season to level matters on the hour mark.

And the tensions which had always threatened to erupt finally boiled over in the last minute of normal time when Gunners midfielder Denilson was sent off for a challenge on David Dunn.

Wenger's young side was dealt another blow in the first period of extra time when substitute Nacer Barazite was carried off on a stretcher with a suspected dislocated shoulder.

But their class told again in the 104th minute when Eduardo struck a clinical winner from 16 yards to encourage hopes of what is essentially Arsenal's reserve side reaching the final of the competition for the second year running.

Much of the pre-match talk centred around the bitter feud which has developed between the clubs since Blackburn were branded the bully boys of English football a few seasons ago.

Tensions simmered throughout the second half, culminating in Denilson's dismissal, but the first 45 minutes was all about the pace and panache of Arsenal's brilliant youngsters.

Out went the 11 established names who beat Barclays Premier League rivals Chelsea 1-0 at the Emirates Stadium on Sunday.

In came the likes of goalkeeper Lukasz Fabianski, Justin Hoyte, Armand Traore and Mark Randall - none of whom have even featured in the Premier League this season.

Blackburn, currently faltering in the League, struggled to cope and Arsenal quickly assumed total control.

Danish striker Nicklas Bendtner, 19, held the key to their early dominance.

Diaby's sixth-minute opener was the product of a bewildering spell of inter-passing, typical of the free-flowing football Wenger has made customary at Arsenal.

It began when Bendtner was set free down the right flank and culminated in Diaby sweeping home his cross with left-footed half-volley which flew past Brad Friedel and nestled in the top corner.

The familiar cry of '1-0 to the Arsenal' soon rang out from the legions of travelling fans.

A ninth-minute move almost delivered a second goal and again Bendtner was the architect - the towering Dane playing an intelligent one-two with Diaby before racing clear down the left flank.

Bendtner advanced forward at pace and placed the ball almost perfectly into the top corner, but could only watch in agony as his shot cannoned off the crossbar.

Arsenal began to dominate possession and clear-cut chances continued to be created.

Rovers then forced two smart saves in quick succession from Fabianski following fierce long-range strikes from Dunn and Bentley.

Having survived Blackburn's brief purple patch, Arsenal hit back in devastating fashion to double their advantage on the half-hour mark.

Denilson, dictating play alongside Lassana Diarra in the centre of midfield, spotted Eduardo making a darting run behind the home defence.

His pass was testing but Samba failed badly to clear the danger, allowing Eduardo to collect possession and place a left-foot shot into the corner of the net past an exposed Friedel.

Blackburn were clearly shocked but they rallied again and were rewarded when Santa Cruz volleyed home Matt Derbyshire's right-wing cross.

The second half saw tackles fly in from both sets of players as the pendulum began to swing towards Blackburn.

And after Mark Randall was booked for a challenge on Stephen Warnock, Bentley stepped up to deliver the resulting free-kick from the left flank which Santa Cruz dispatched with a far-post header.

Both sides created several half-chances in the latter stages of the game, which ended in acrimony when Denilson was sent off for a challenge on Dunn before getting involved in a fracas with Robbie Savage which earned the Blackburn midfielder a booking.

But Eduardo's ice-cool finish - a low left-footed strike from 16 yards - proved the winner and Arsenal could celebrate another momentous victory after Samba's late header cannoned off a post.