Neil Warnock is expecting the toughest test yet for his Premier League slayers in the FA Cup at Manchester City on Sunday (2pm).
The boss is proud of how his squad have performed in the domestic cups this season and believes that our results would be a triumph for any team.
"We've done brilliantly in the cups this year," said Warnock. "I don't think anybody has done better than us.
"We've had a very good cup run and it shows what ability we have in the squad, that's what makes it more frustrating in the league."
This season United have beaten Premier League opposition in the form of Everton, Southampton and most recently high-flying Tottenham Hotspur. But the manager believes Manchester City on Sunday will be the toughest test his side have faced this season.
"This is by far the toughest one, the champions of the Premier League," said Neil.
"We are away from home and it's the only competition they have got left to win.
"It's going to be difficult but we've got to go and enjoy it as no league points are on offer - I'm sure the fans will go there and enjoy it as well."
"The cup gives us the opportunity to play against the champions of England and the fans will turn out in full and I'm sure they will enjoy the afternoon."
As with United's previous Premier League opponents, we will be heading into Sunday's game as the underdogs but that suits the manager just fine.
"I don't think we'll bother looking at a video of Man City, we looked at one for Chelsea," said Warnock.
"The bookmakers don't get much wrong so we know we are up against it.
"But we want to give a good performance, we want the fans going over there to enjoy their day and we don't want to come away after a drubbing.
"The fans going to the Etihad will be thinking we should be travelling here every year and I'm sure it won't be too much longer before that's the case.
"We've got some good players here and we can cause them some problems. They've got to relish playing against some of the best players in the world."