Derby boss Nigel Clough is hoping a seed of doubt has been sown in the mind of the normally self-assured Sir Alex Ferguson.
Just over five weeks ago, Clough watched from the Pride Park stands as Derby pulled off a remarkable shock by beating Manchester United 1-0 in the first leg of their Carling Cup semi-final.
Clough had been officially appointed as manager of the Rams the day before, and took on a watching brief for that game, with caretaker David Lowe in charge on the sidelines.
It was a weakened United side that took to the pitch on that night, and although Derby were defeated 4-2 in the second leg at Old Trafford, they still caused Ferguson a number of headaches.
Clough believes those two games will have given Ferguson food for thought ahead of Sunday's FA Cup fifth-round tie at Pride Park.
Although Ferguson has conceded the FA Cup is low on his list of priorities as his team chase five trophies, Clough is convinced he will not want to be embarrassed like he was on January 7.
"We showed we could cause them problems over the two matches, and certainly we did down here," said Clough, as he sat in the trophy room at Pride Park. Defensively in the first half at Old Trafford we weren't very good and that is why we lost the tie at Old Trafford. "But apart from that, going forward we created chances, scoring three goals in the two games, which is a rarity against United these days.
"Certainly, I think the home leg will have a bearing, even though there are bigger competitions in their eyes, given the Champions League and Premier League. "I think they will be a bit more cautious. If they had come here and won two or three nil, he (Ferguson) would probably think he could put the same side out and do it again. "But there will be a little doubt there, and in the players' minds as well we hope."
As far as Clough is concerned, it has been business as usual this week, with barely a word mentioned in training about United. That is a trait adopted by his father, Brian, who never mentioned a word about the opposition in the build-up to matches.
On this particular occasion, it is with good reason there has been little said about United, recalling a conversation three years ago ahead of former club Burton's famous goalless draw in the FA Cup with the Reds.
"Another manager phoned and said to me 'Have you spoken to the players about their fears?"' cited Clough. "I said 'No', and he replied 'Well, I think you should'. "That prompted me to say 'Well, if we start talking to them about their fears then they will have some!'
"We don't want the players to have any fears, so the last thing you want to do is talk to them about it. "It's been the same this week. If you run through their side the lads would be petrified. "We all know how good they are, so there's no need to emphasise or highlight it.
"All we have to do is relax and play. There's no point getting too nervous, too het up, and think we're playing Manchester United, the best team in the country, the world or whatever. "We just have to say 'Hold on a minute', calm ourselves down and play our stuff as well. It's very important we do that.
"So we're preparing exactly the same for them as for anybody, the same as it will be for Blackpool on Wednesday - which I hasten to add is a more important game for us."
Clough, who believes lightning can strike twice in a one-off cup competition, stands on the brink of what would be a rare double over United. "If we lose, forget it - it wasn't important anyway!" joked Clough. "But if we win, we will be shouting from the rooftops and using it as much as we can."
The Rams are without the suspended Jay McEveley, whilst Luke Varney is sidelined with a groin strain.
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