The two teams will meet in the first of the last-four ties in a 1730 kick-off at Wembley, with the winners taking on either Leicester or Southampton in the final on May 15.
City also boast a healthy lead at the top of the Premier League, are through to the last four of the Champions League and will be back at the national stadium the following weekend for their Carabao Cup final against Tottenham.
“Do it with a smile. We are not tired. If you are tired, you don’t like this game.
“But at the same time as being a privilege I know right now we could finish without a title. I have a feeling (Manchester) United are in top form and you have to win games to win the Premier League.
“Everyone says it is impossible but in football anything can happen. We could lose four or five games in a row. In football it can happen.”