Manchester United made light work of a struggling Nottingham side thanks to some brilliant attacking football and incisive finishing.
Manchester United vs Nottingham first half
United began the game on the front foot as expected and the early pressure was as persistent as the rain that poured down at Old Trafford during an entertaining first half.
Tyrell Malacia saw a fierce drive turned onto the post by Forest goalkeeper Wayne Hennessey, and on the 20-minute mark, United took the lead.
Christian Eriksen displayed his customarily superb vision to slide his corner kick into the path of Rashford, who guided home from close range for his 10th club goal in all competitions this season.
The Red Devils doubled their advantage three minutes later, courtesy of an attack that started with a tenacious Casemiro challenge on Taiwo Awoniyi deep in the Manchester United half.
Bruno Fernandes played a perfect pass down the left into the path of Rashford, who burst forward and chopped inside Serge Aurier before finding Anthony Martial, to finish past Hennessey for 2-0.
Just before half-time, Forest had a goal ruled out for offside after a VAR review and United went into the break two goals to the good.
Manchester United vs Nottingham second half action
United came into the second half hungry for more goals. Rashford again turned on the style, sliding a wonderful through-ball to Fernandes, but his pass to Antony was repelled by Hennessey.
The Red Devils went close again through Martial but the Forest keeper stayed sharp. Antony and Martial were withdrawn for Donny van de Beek and 18-year-old Alejandro Garnacho soon after.
Late substitute Fred sealed the three points for United on 87 minutes, applying a cool finish to a perfect pass from the outstanding Casemiro.
The loss left Nottingham Forest still searching for their first Premier League away win and just one place off the bottom of the table.