Ole Gunnar Solskjaer says Manchester United need to harness the spirit shown against Paris St Germain and put in a "perfect performance" if they are to navigate their way past Manchester City and reach the Carabao Cup final.
United face an uphill battle in their attempts to reach March's Wembley showpiece after a chastening 3-1 home loss in the semi-final first leg against Pep Guardiola's men three weeks ago.
Marcus Rashford's goal in that Old Trafford encounter gives United a glimmer of hope heading to the Etihad Stadium on Wednesday, but Solskjaer is under no illusions about the task that awaits them.
Despite that, the Norwegian believes last year's stunning comeback success against PSG - United won 3-1 in Paris to reach the Champions League quarter-finals on away goals, having lost 2-0 in the home leg - can act as inspiration, along with December's impressive 2-1 triumph at City.
"Well, it looked like it was over at half-time," Solskjaer said, reflecting on the first leg. "I have to say the second part of that first half, they outplayed us for a while and it's hard.
Pep Guardiola remains wary of the threat posed by Manchester United in Wednesday's game, after his side were beaten 2-1 at the Etihad in the Premier League earlier this season.
Liverpool boss Jurgen Klopp faced criticism for saying he would not be in charge for his side's upcoming FA Cup replay against Shrewsbury and that the Reds would send their Under-23 side to play the game, with the newly-introduced winter break in force at that time.
Guardiola supported Klopp's stance, saying: "We accept the schedules and the competitions, games every two or three days, but don't tell the managers which players to pick."