Erik ten Hag's Manchester United began abysmally against Forest and conceded twice inside the opening five minutes to Steve Cooper's enterprising outfit.
United got the quick response they needed however with Marcus Rashford's cut back being touched in by Cristian Eriksen.
Dejan Kulusevski sealed the points in the second half for new manager Ange Postecoglou's side.
First half I thought we were really good," Australian Postecoglou, who has quickly changed the mood at Spurs, told reporters.
Champions Manchester City, who are fifth on six points, visit promoted Sheffield United on Sunday when Newcastle United, on three points, host Liverpool who have four.
Persons:
Manchester United's Bruno Fernandes, James Ward, Prowse, Jarrod Bowen, Michail Antonio, West Ham, Erik, Steve Cooper's, Fernandes, Forest, Andre Onana, Willy Boly, United, Marcus Rashford's, Cristian Eriksen, Casemiro, Joe Worrall, Danilo, Rashford, Andreas Pereira, Bukayo Saka, Aaron Ramsdale, Eddie Nketiah, Calvin Bassey cynically, Marco Silva's, Arsenal's, James Maddison, Dejan Kulusevski, Ange Postecoglou's, we've, We've, Sasa Kalajdzic, Crystal Palace's Joachim Andersen, Kevin Schade's, Martyn Herman, Ken Ferris
Organizations:
Manchester United, Forest, Arsenal, Fulham Flying West Ham, Manchester, Nottingham Forest, Fulham, Premier League, . West Ham United, Brighton & Hove Albion, Tottenham Hotspur, Bournemouth, Hammers, Seagulls, United, Bukayo, Spurs, Everton, Wolverhampton Wanderers, Wolves, Brentford, Manchester City, Sheffield United, Sunday, Newcastle United, Liverpool, Thomson
Locations:
Brighton, ., West, Portuguese, Forest's, London