Former Forest winger Commons sent the Rams through to a last-16 tie at home to Manchester United later this month with a deflected second-half effort.

Derby had seemed down and out when they quickly fell two goals behind.

Chris Cohen gave the Reds a dream start with a goal after only 60 seconds before Nathan Tyson doubled their lead from the penalty spot in the 14th minute.

Rob Hulse halved Derby's deficit with a well-placed header as the half-hour mark approached and another header from Paul Green restored parity before Commons struck.

The Arctic conditions did little to detract from the white-hot atmosphere inside the City Ground at kick-off.

And Cohen was soon to raise the noise levels by several decibels.

The midfielder collected a return pass from his own short corner and, after taking a touch to make the shooting angle more favourable, curled a left-foot shot past the unsighted Stephen Bywater from the edge of the area.

The Forest fans that jeered Commons' every touch momentarily stopped to hold their breath when his curling shot looped inches past the far post after seven minutes.

Matt Thornhill looped a header narrowly wide and Lewis McGugan stung Bywater's palms with a fiercely-struck volley before Forest extended their advantage.

Tyson broke the offside trap and raced goalwards before being tripped by Bywater as he took the ball round the Derby keeper.

Referee Chris Foy wasted no time in pointing to the penalty spot. Bywater was shown a yellow card and was arguably fortunate not to see red after denying Tyson a clear-cut scoring opportunity as the last man.

Tyson dusted himself down, however, and fired the ball into the top corner.

Derby responded well and Commons forced Paul Smith to block a powerful shot from the right-hand side of the area midway through the first half.

The Rams halved their deficit in the 28th minute when Hulse rose unchallenged at the far post to guide Gary Teale's left-wing cross into the opposite corner.

Cohen's low shot had to be palmed away by Bywater at the start of the second half.

But Derby were in the ascendancy and they equalised on the hour when Green took advantage of some more statuesque Forest defending to head home another Teale cross.

A swift counter-attack almost saw Forest retake the lead four minutes later.

Tyson led the charge, collecting Smith's long throw on the halfway line before advancing to the edge of the area where he swung a low cross into the six-yard box.

But Garath McCleary did not get the desired contact and his prod goalwards hit Bywater and rolled agonisingly wide.

Green dribbled a shot narrowly wide midway through the second half before a thunderous shot from Commons - reminiscent of the one he unleashed in the Carling Cup semi-final first-leg defeat of Manchester United - cannoned back off the foot of the post.

However, Commons finally did find the net in the 73rd minute and it proved to be decisive.

The Scotland international wrong-footed Wes Morgan and created a yard of space for himself.

His shot clipped Morgan as the Forest defender tried to recover and the ball looped beyond Smith and into the far corner.

Substitute Mark Byrne had a golden opportunity to force extra-time with two minutes remaining but the youngster took a heavy touch when trying to control Morgan's cross and scuffed his far-post shot wide as Bywater closed in on him.