When these two teams met back in August Derby took full advantage of a fed-up Fulham side and thrashed them 5-1.
Fast forward two months and the Cottagers are a very different proposition indeed. Since the departure of deeply unpopular manager Felix Magath, they have been rejuvenated under the command of caretaker boss Kit Symons, who has steadied the ship and won an impressive five of his eight games in charge.
Reaching the quarter-finals of the League Cup would boost his chances of getting the job permanently.
Whether he is awarded the job full-time remains to be seen but he says he is "very confident I'll get it" and he would clearly be a popular appointment with players and fans alike.
Championship table toppers Derby were shocked at home by struggling Wigan at the weekend and a highly unimpressed head coach Steve McClaren admitted, "I would love to have made seven or eight substitutions at half time."
He could make a similar number of changes to his side for this fixture after admitting some of his players are feeling the pace.
"I think Will Hughes has played three games a week for the last six weeks," said McClaren. "May be we should not have played Will and rested him.
"We need our energy and we didn't have that, we did not play football".
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Fulham have scored eight goals in their two previous League Cup games against Derby, which came in successive seasons in 2000-01 and 2001-02.
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This is the 54th meeting between the sides. Derby have won 19 matches, Fulham 17 and there have been 17 draws.
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Fulham have made the fourth round in consecutive seasons for the first time since 2002-03. Last season, they were eliminated at this stage by Leicester City.
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The Whites have scored in 30 of their last 31 home games in this competition, including the last 21 in a row.
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Indeed the last 17 League Cup games at Craven Cottage have averaged 4.5 goals per game.
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The Rams ended a run of eight without a win in all competitions against Fulham with a 5-1 drubbing at Pride Park in August.
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Since their latest relegation from the Premier League, Derby have won three of their four League Cup ties against fellow Championship sides.
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Defeat to Wigan on Saturday was Derby's first defeat in 13 matches and only their second of the season.