Burnley's Carling Cup campaign to an end against Premiership Portsmouth, who may have been lucky to escape with their second 1-0 win in East Lancashire in the space of three days.

Boss Steve Cotterill made five changes to the side that drew 2-2 with Bristol City at Ashton Gate on Saturday with Lafferty, Akinbiyi, Unsworth, Mahon and Spicer coming into the side.

But despite a new 4-1-4-1 formation, it was Pompey who progressed into the last 16 thanks to a controversial second half goal from former Preston North End striker David Nugent.

It was the Clarets who started the brighter, with some good attacking play which was let down by a slightly wayward final ball.

The first real chance came in the 11th minute when a through ball from Lafferty was cut out by Distin before Akinbiyi could connect at the near post.

Clarke Carlisle took the clearance down well on the edge of the box from the resulting corner but his shot curled wide of Ashdown's left hand post.

Pompey's first real effort came on the quarter hour mark when Pedro Mendes fire an ambitious long-range effort wide of Kiraly's goal.

Just a couple of minutes later Akinbiyi went close, but he again had the ball nipped of his toes before he could get his shot away.

Nugent then spurned a golden opportunity, gaining the benefit of the doubt when looking well offside but made to look foolish when Kiraly nicked it off his toes as he tried to ealk thre ball around the Hungarian.

Just after the half hour mark Steve Caldwell's point blank header from a Mahon corner was superbly saved by young Pompey keeper Jamie Ashdown.

And a couple of minutes later a loop Lafferty header was dealt with well by Ashdown under his bar.

However, Kiraly was active too and he kept Burnley level on 37 minutes, pulling off a great save after a good effort from Matt Taylor in the area.

The Clarets continued to push and won their eighth corner of the game on 40 minutes - but a cross into the box was nicked off the head of James O'Connor by Akinbiyi who failed to spot the Ulsterman behind him.

That was the last action of the first half and at the interval Pompey boss Harry Redknapp shuffled his pack, bringing on the pacy John Utaka for the out-of-sorts Benjani who struggled upfront in the first half alongside Nugent.

But it was the latter who had the first real chance of the second half on 50 minutes. Despite being unmarked, he floated his header back across goal and out for a Burnley goal kick, much to the delight of the Clarets faithful.

Mahon broke through a couple of minutes later but his attempt to put Akinbiyi in on goal went badly wrong and Ashdown was pleased to see the ball run through to him.

The midfielder then had a long range effort which sailed over Ashdown's goal as the Clarets looked to end a disappointing spell which saw them forced to scrap for the ball in the middle of the park.

That seemed to kick-start Burnley and Lafferty tested Ashdown just a couple of minutes later with a good turn and shot from the edge of the box.

However, Nugent gave Portsmouth the lead on 67 minutes after breaking behind the Burnley defence. Despite what looked to be a handball the England striker raced down on Kiraly's goal and slotted it past the goalkeeper before celebrating in front of the Burnley fans in the James Hargreaves Stand.

With the Clarets now chasing the game, Cotterill threw caution to the wind on 75 minutes and introduced Robbie Blake and Graham Alexander in place of Unsworth - who played well in front of the back four - and James O'Connor.

And as Burnley tried to force the issue in the last 10 minutes, Alan Mahon's speculative effort from 35 yards bounced in front of Ashdown and caused the keeper some problems before David James' understudy was able to gather at the second attempt.

A low free kick was then blasted into the Portsmouth wall by Blake and the last chance of the game came and went as Portsmouth went into the hat for the fourth round.

Burnley: Kiraly, Duff, Carlisle, Caldwell, Jordan, Mahon, Spicer, O'Connor (Alexander 75), Unsworth (Blake 75), Lafferty (Steve Jones 81), Akinbiyi. Subs: Alexander, Gudjonsson, Jensen, Jones, Blake.

Booked: J O'Connor, Kiraly

Portsmouth: Ashdown, Lauren, Pamarot, Traore, Mvuemba (Diop 90), Mendes, Hughes, Taylor, Nugent, Benjani (Utaka 45), Distin. Subs: James, Cranie, Diop, Utaka, Kranjcar.