A Marlon Harewood brace gave Forest victory over 10-man Sheffield United at the City Ground, but the home side's promotion hopes suffered a serious blow after striker David Johnson broke his leg.
Johnson fell to the ground in agony after taking a shot in the 11th minute, and hospital tests confirmed he had a fractured tibia.
Harewood struck either side of half-time, and Andy Reid made sure of the points for Paul Hart's side with a 71st-minute strike.
The Blades had levelled Harewood's first-half penalty when Peter Ndlovu scored from the spot, but their hopes were hit when Chris Morgan was sent off for violent conduct after an hour.
Forest went ahead on the half-hour when Harewood scored from the penalty spot after being up-ended by Robert Page, but they were unfortunate not to be ahead by a bigger margin at the interval.
Forest won a corner inside the opening three minutes of the first half, but Reid's flag-kick was cleared by Page.
Just seconds later Matthieu Louis-Jean tried his luck, but his shot flew over the visitors' crossbar.
Forest continued to enjoy the better of the exchanges.
United, who appeared rattled by Forest's early supremacy, continued to give away free-kicks - and Danny Sonner let fly from 25 yards only to see his shot clear the crossbar.
Sonner then went close with a shot which was parried by visiting goalkeeper Paul Gerrard, who then had to save again from the lively Johnson.
But Johnson had to be replaced by Gareth Taylor after sustaining his injury.
Even so Forest dominated large parts of the game and still had plenty in reserve when the visitors did threaten a comeback.
Nott'm Forest: Ward, Louis-Jean, Dawson, Thompson, Morgan, Sonner, Williams, McPhail, Reid, Johnson, Harewood. Subs: Jess, Roche, Stewart, Taylor, Walker.
Sheff Utd: Gerrard, Jagielka, Morgan, Page, Kozluk, Ndlovu, Montgomery, Rankine, Tonge, Peschisolido, Allison. Subs: Ward, McCall, Parkinson, Armstrong, Cryan.
Referee: M Pike (Cumbria).