Nottingham Forest full-backs Julian Bennett and Luke Chambers came up with the goals which saw off a poor Millwall side at the City Ground.
Bennett powered in a 47th-minute header from a Kris Commons corner to give Forest the lead.
And Chambers slotted in the second 11 minutes later after Millwall had failed to clear a Wes Morgan header.
Morgan also headed against the crossbar from another Commons corner, while Millwall barely managed a shot.
Nottm Forest: Smith, Chambers, Wilson, Morgan, Bennett, Clingan, McGugan (Davies 85), Cohen, Commons (Perch 82), Tyson, Hoskins (Holt 69).
Subs Not Used: Breckin, Sinclair.
Booked: Bennett, Holt.
Goals: Bennett 48, Chambers 58.
Millwall: Evans, Bignot, Robinson, Whitbread, Frampton, Simpson, Fuseini, Laird, Brkovic (Martin 58), Alexander, Harris (Grabban 67).
Subs Not Used: Pidgeley, Senda, Forbes.
Booked: Whitbread, Frampton, Bignot.
Ref: Clive Oliver (Northumberland).