"It is a game that you play as you see. The only thing I think will have any bearing is if we play like we did on Sunday," he says.
"The rest of the games I have been involved in have been good performances throughout the team, and at the end of the day we know what we are capable of doing.
"The fact we have already beaten Chelsea earlier in the season means arguably there is nothing to worry about, but it is about how we perform, and we have to get ourselves right for Saturday.
"I wouldn't say Saturday is a chance to rectify things because it is a different competition and a different game - but we have to sort ourselves out for Saturday and to get back into a good run."
Prior to the defeat at Stamford Bridge, David had conceded just nine goals in 10 games - and only five away from home, including the 3-0 defeat by Leeds - but now it is 14 in 11.
He says: "The thing is, I'm gutted because it is the first time I have let five goals in in my career, which is obviously something I didn't want to do.
"But, although it is never good losing games, it has happened and we have to turn it round and win the next game. The goal is to sort things out and go through to the next round of the cup.
"Losing hurts, first and foremost, and the scoreline has added effect but Saturday is an opportunity to put things right."
Despite his disappointment at conceding five, he is forcing himself to be philosophical and hope for a good response to the loss at the weekend.
"That's the way it is," he says, "and one thing about a defeat is that when you lose you get no points. Whether it is 1-0 or 5-1 the points tally is always the same.
"Goal difference might be an issue but ultimately, strange as it may sound, you are 'better' off conceding more goals so people realise there is a problem.
"That happened earlier in the season after the Blackburn and Everton games - and things turned round pretty sharpish, because they had to.
"Likewise after yesterday, on analysing the video a few things have been highlighted and we will have to sort them out.
"How did I see it? We gave away two bad goals and it wasn't good at all.
"The disappointing thing is we gave away a bad goal to start with from the corner when we didn't pick up two players. Gudjohnsen has had a shot and then obviously Hasselbaink has scored courtesy of a little deflection off Michael Carrick.
"There is never a good time to let a goal in but there especially and we started the second half badly and never really got into it at all. Jermain has done well, coming on to score, but obviously a little bit too late there, and basically Chelsea have dominated the game.
"It didn't help when Paolo got sent off - but it is just disappointing overall."
David particularly rues the first goal which set them on their way, and he adds: "You not going to score five without scoring one, are you?
"But the manner in which it was conceded was, as I say, disappointing, with two unmarked players leading to the goal."
But he also understands that if things are not going right at one end of the pitch, you hope for some luck, which you have to create, at the other.
But that was not forthcoming, and he says: "What breaks? We didn't create them. Even in the first half it was 0-0 going into injury time and Cudicini has had one half save to make.
"Ultimately you are going to score goals from getting shots in, and I think we made it a little bit hard for ourselves."