In an interview with Liverpool media, Joe Gomez said: "The way it ended last time round in the FA Cup [quarter-final] was pretty disappointing for us.
"We obviously had good phases in the game and we couldn’t see it out but, onto the next.
"It’s a different competition, we know we’ll have to bring momentum there, it’s a tough place to go and they [Manchester United] are still a top team so we have to be at it and ready.
"We have to be ruthless and take our chances to see out games, and things can swing so quickly.
"So, hopefully we have control again and we can get in that position to punish this time."
Gomez also expects Man United to come out with all guns blazing in attack on Sunday.
He added: "I mean, they’re at home. I don’t think the atmosphere [and fans] would appreciate them playing a low block and sitting off so I’m sure they will be up for it and will come out at us, and it’s up to us to deal with that atmosphere and go for them."
Man United have lacked a distinct style of play this season partly due to the disjointed team selection due to injuries.
Liverpool have also had injury issues but they are in great form and at the top of the Premier League table.
22 points separate the two sides in the standings, with Jurgen Klopp relishing the prospect of an upset after losing the FA Cup quarter-final. This could also be Klopp's final game as Liverpool boss at Old Trafford, meaning his team will be eager to make it extra special.
The fixture could not have come at a worse time for Man United, who have a threadbare defence and the growing pressure of back-to-back poor results.
