Karl Hawley grabbed a first-half winner to hand a spirited Carlisle side a hard-earned home victory. Carlisle's goal came when the unmarked Hawley nodded home from six yards from Paul Thirlwell's lofted pass.
Nottingham Forest enjoyed plenty of possession in midfield but were unable to breach a solid United defence.
Forest pressed in the final fifteen minutes, but it made little difference against the rearguard in which Peter Murphy and Danny Livesey excelled.
Carlisle: Westwood, Raven, Murphy, Livesey, Aranalde, Gall, Thirlwell, Murray (McDermott 88), Smith, Garner (Holmes 90), Hawley.
Subs Not Used: Williams, Gray, Joyce.
Goals: Hawley 45.
Nottm Forest: Smith, Curtis, Breckin, Morgan, Bennett, McGugan, Clingan, Perch, Grant Holt, Dobie (Agogo 76), Lester (Tyson 76).
Subs Not Used: Redmond, Gary Holt, Bencherif.
Booked: Bennett, Grant Holt, Curtis.
Att: 9,022
Ref: D Drysdale (Lincolnshire).