Jed Wallace's 72nd-minute strike secured a priceless three points for Millwall at Derby County in the Sky Bet Championship on Wednesday night.
In a lowkey affair that lacked clear-cut chances, the winger took his 18 minutes from time to lift The Lions five points clear of the bottom three in the League table.
Millwall boss Neil Harris made two changes from Saturday's Emirates FA Cup victory at AFC Wimbledon, with Shaun Hutchinson replacing the ineligible Alex Pearce at the heart of defence, and Ben Marshall returning instead of Aiden O'Brien.
The first opportunity of the evening went the way of Millwall, but with five minutes on the clock, Mahlon Romeo's cross flashed across the face of goal without a touch.
The Lions soaked up a lot of possession in the first 20 minutes without Derby threatening, but they found a way past the defence shortly after - Martyn Waghorn, however, overran his touch and the ball rolled out of play.
A quiet first-half rolled on, with the next moment of note being Tom Huddlestone's effort from distance four minutes from the break, which sailed harmlessly over Jordan Archer's crossbar. There were then shouts for a penalty-kick in stoppage-time, but referee James Linington was unmoved, despite Jack Marriott's protests.
Two minutes into the second-half The Rams swung over a corner, but Richard Keogh's turned Duane Holmes' kick wide. Marriott then controlled well and looked to pull the trigger, but he scuffed his shot, allowing Archer to claim with ease.
With 55 minutes on the clock a cross from Jed Wallace caused problems for Derby stopper Kelle Roos, but the ball shaved the crossbar before landing to safety on the other side of the pitch. At the other end, Harry Wilson sent a free-kick over.
On 72 minutes The Lions took the lead. Millwall broke away and a through-ball found Jed Wallace, who took on his marker and fired a left-footed shot past Roos for his fifth goal of the campaign.
Millwall dropped deeper in their attempt to protect the lead, with Archer having to dive full stretch and palm away a header inside four minutes of stoppage-time - a period that The Lions negotiated to secure three vital points.
Derby County: Roos, Bryson, Tomori, Keogh, Wilson (Nugent 86'), Waghorn, Marriott, Holmes, Cole (Jozefzoon 73'), Bogle, Huddlestone (King 73'). Subs not used: Ravas, Wisdom, Johnson, Malone.
Booking: Huddlestone, Keogh
Millwall: Archer, Hutchinson, Cooper, Williams, J. Wallace (Tunnicliffe 88'), Gregory (Elliott 75'), Ferguson, Romeo, M. Wallace, Leonard, Marshall. Subs not used: Martin, Thompson, Onyedinma, Morison, O'Brien.
Scorer: J. Wallace 72'
Booking: Marshall, Williams, Elliott
Referee: James Linington
Attendance: 24,907 (377)