Nigel Clough was left to reflect on what could have been after Derby missed their chance to reach the Carling Cup final.

Derby were surprise 1-0 winners in the first leg but United went in at half-time of the return 3-0 up thanks to goals from Nani, John O'Shea and Carlos Tevez.

Derby then threatened an upset when Giles Barnes scored from the penalty spot to put his side back in it.

Cristiano Ronaldo's penalty gave United a two-goal cushion and Giles' second proved to be nothing but a consolation as United claimed their passage to the final with a 4-3 aggregate win.

"If we would have got the second at home maybe things could have been different," Clough told Sky Sports 1.

"We couldn't do anything about the first goal tonight but the second was a killer really.

"Rob Hulse had a good chance with a header but nothing seemed to drop for us. It was good for Giles to get a couple, he's been out for a long time ."

Clough admitted that his side's performance was a marked improvement on his first game in charge which ended in a 2-0 loss against QPR.

"It was a big improvement actually on Saturday," he added.

"We kept playing and plugging away and we showed a lot of character after Saturday. That's what I was looking for."

"United can beat anyone on their day by four, five or six so we have a lot of positives to take from tonight."