The Tricky Trees edged past Wolverhampton Wanderers on penalties to make the final four, while the Red Devils comfortably saw off Charlton Athletic in the quarter-finals, and the two sides will reconvene for the second leg at Old Trafford on February 1 for the chance to meet Newcastle United or Southampton at Wembley.
Match preview
Only a few months on from the threat of a relegation dogfight as their plethora of new signings struggled to gel, Nottingham Forest are potentially only 180 minutes away from a memorable trip to Wembley and have established a healthy lead above the Premier League drop zone.
Grimsby Town, Tottenham Hotspur and Blackburn Rovers all fell to Forest's superiority in the earlier rounds of the EFL Cup before they played out a 1-1 draw with Wolves after 120 minutes, but Dean Henderson was the hero in the shootout, saving from Ruben Neves and Joe Hodge to send the Tricky Trees through.
The injured Henderson - who would not have been able to face his parent club anyway - will watch on with bated breath as Forest attempt to reach the EFL Cup final for the first time since 1992, where they lost to Manchester United, and Wednesday will mark the four-time winners' first semi-final appearance for 31 years.
Steve Cooper's side came from behind to rescue a 1-1 draw against Bournemouth in Saturday's Premier League contest, as Sam Surridge responded to Jaidon Anthony's effort against his former club, stretching their unbeaten run in the division to four games as they sit in 13th place in the table.
Welcoming Man United to a ground where they are unbeaten in eight successive games in all tournaments and have scored in 10 consecutive matches since August, Nottingham Forest are not to be taken lightly, especially considering that they have played six EFL Cup semi-final ties and progressed from all six.
Man United, mathematically speaking, are still fighting for success on four fronts this season, but even the most optimistic of Red Devils supporters may consider a Premier League title charge to be out of the question following their pulsating five-goal thriller with Arsenal.
The Gunners were facing the only side to have beaten them domestically this term, and Eddie Nketiah's brace and Bukayo Saka's sensational strike completed their revenge mission, but Marcus Rashford and Lisandro Martinez also contributed to one of the best games of the Premier League season so far.
Having fallen 11 points behind the league leaders - who also have a game in hand - the EFL Cup presents a more immediate shot at early silverware for Erik ten Hag, whose team have sent Charlton Athletic, Aston Villa and Burnley out of the tournament to progress to the final four.
Jose Mourinho led the Red Devils to EFL Cup glory in 2017 - their fifth time going all the way in the tournament - but they have since suffered two semi-final eliminations to Manchester City in 2020 and 2021 and are now at risk of going three games without a win for the first time under Ten Hag.
However, Man United's last five EFL Cup games away from home have ended in victory - with their most recent four also seeing the Red Devils pick up a clean sheet - and Ten Hag's side eased past Forest 3-0 at Old Trafford just after Christmas.
Nottingham Forest EFL Cup form:
W
W
W
W
Nottingham Forest form (all competitions):
D
W
L
W
W
D
Manchester United EFL Cup form:
W
W
W
Manchester United form (all competitions):
W
W
W
W
D
L
Team News
Wayne Hennessey will continue to act as the last line of the Forest defence as Henderson recovers from a thigh injury, and the Man United loanee is joined in the infirmary by Taiwo Awoniyi, Cheikhou Kouyate, Omar Richards, Moussa Niakhate and Giulian Biancone.
Ryan Yates was only able to play the first half of Forest's draw with Bournemouth due to illness, allowing Danilo to come in for his debut, and the former Palmeiras midfielder may even be considered for a starting role here after a bright second-half cameo.
Winter arrival Chris Wood is also cup-tied for this contest following his previous exploits with Newcastle United, which opens the door for Gustavo Scarpa to return as Morgan Gibbs-White and Brennan Johnson form the strike partnership.
As for Man United, Ten Hag will welcome Casemiro back to the team with open arms after the Brazilian missed the loss to Arsenal through suspension, which should spell the end of Scott McTominay's brief time in the starting XI.
Axel Tuanzebe and Donny van de Beek remain sidelined for the Red Devils, who are also unlikely to welcome Jadon Sancho - who is now in team training - back to the fold so soon, while Anthony Martial (leg) and Diogo Dalot (hamstring) are facing races against time to be fit as well.
Ten Hag should save the bulk of his rotations for the weekend's FA Cup clash with Reading and go with a strong XI from the off at the City Ground, but Alejandro Garnacho and Tyrell Malacia are among those who can feel hopeful of recalls.
Nottingham Forest possible starting lineup:
Hennessey; Aurier, Worrall, Boly, Lodi; Mangala, Danilo, Freuler; Scarpa; Johnson, Gibbs-White
Manchester United possible starting lineup:
De Gea; Wan-Bissaka, Varane, Martinez, Malacia; Casemiro, Eriksen; Antony, Fernandes, Rashford; Weghorst
We say: Nottingham Forest 1-2 Manchester United
Nottingham Forest are slowly but surely proving that they are to be taken serious at this level, and not many teams have been able to keep Cooper's side at bay at the newly-fortified City Ground.