Rangers are braced to face the SPFL Premiership club without Lee Wallace, Andy Little or David Templeton.
Gavin Gunning, the United central defender, acknowledged that the Tannadice side expected to reach the final. Asked if his team could add to Rangers misery after the Ramsdens Cup final defeat at Easter Road on Sunday, the defender said: "That should be the case because we have a really good squad full of really good players. You would like to think that if we turn up and do our stuff then we will win."
United, too, want to profit from any nerves on behalf of a side that lost 1-0 to Raith Rovers at Easter Road, prompting boos from their support.
"An early goal against will get any set of fans on any team's back," said Gunning. "If you concede an early goal it is always a bit tentative."
However, Gunning believes that Rangers are a better side from the one which United beat last year in the Scottish Cup. "They have improved since then," he said. "They have shown great consistency throughout the season and that means it will be a tough game for us.
"Last year, getting the early goal helped us a lot. I think it was the first minute of the game and that kind of killed them a bit."
The 23-year-old expected a strong Rangers reaction from the Ramsdens Cup defeat, though.
"We would probably have preferred it had Rangers beaten Raith. I say that because they will obviously be more up for this game knowing it is the only cup they have a chance of winning now," he said. "The Rangers lads are professionals so they just have to get on with it and focus on the next game. We are the same after our defeat by Celtic last weekend."
Ally McCoist, the Rangers manager, does not expect Wallace, Little or Templeton to feature in what is the biggest match of the season for his side.
The Rangers manager can be consoled that Jon Daly, Nicky Law, Ian Black, and Nicky Clark, who were injury doubts for the Ramsdens Cup final, emerged unscathed physically from the defeat.
But he told the Rangers website: "Lee Wallace has a hip flexor problem at the top of his thigh and he's struggling a little bit at the moment."
He added: "We've been a little bit unlucky with injuries at a really important time but we have to prepare the team as best as we can."