The England international wants the Blues to show they can still "mix it at the top" against United and admits they have been too inconsistent so far this season
The Blues, who currently sit fourth in the table, are now 12 points off top spot after an inconsistent first half to the season under Andre Villas-Boas.
But Sturridge has warned that nobody should question the team and claims they have shown with their win over Manchester City earlier in the season that they can still "mix it at the top".
"We are a big club, and I don't think anybody should forget that," he told the club's official website.
"Just because we have had a bit of a bad spell and we haven't been winning as frequently as we have in the past, I think people are doubting the credibility of Chelsea which they should never do.
"We're a great club, and we are going to go out there on Sunday and prove to everybody that we can still compete with the likes of Manchester United.
"We've already shown by beating Manchester City that we can still mix it with the top two and we will be going out there on Sunday to show what we're about."
Sturridge admits that Chelsea have not reached expectations this season but has reminded supporters that they are still a team in transition.
"Of course, against teams that aren't in the top six we want to be winning every single one of those games, if you maybe win four and then draw one that's okay," he added.
"We haven't been as consistent as we would have liked but we're in a progressive stage where all the teams are improving.
"The mood in the camp is very good and everybody is looking forward to going out there and showing what they can do.
"We played some great football against Swansea, we had some good chances and it was just unfortunate we didn't get the win."
The striker, who has featured from the right side of a front three for much of the season, is also hopeful of adding to his tally of 10 goals for the club so far this campaign.
"I can't score in every game because it's difficult from that position," he said. "But hopefully I can carry on producing my fair share of goals and keep getting assists as well.
"It's good that I'm scoring goals, that's what I love doing, I love scoring goals that help the team win games and that's what I'll be striving to do, I want to score as many as I can in order to help us climb the table."