A bizarre goal by Colin Kazim-Richards saw Derby put their takeover uncertainty to one side and beat West Brom 1-0 at Pride Park, with Irish quartet Jason Knight, Festy Ebosele, Callum Robinson and Jayson Molumby all starting.
Kazim-Richards' first League goal since April made it back-to-back wins for Wayne Rooney's team for the first time since February, after the substitute punished a dreadful mix-up between Cedric Kipre and goalkeeper Sam Johnstone.
The goal was Derby's only effort on target but it was enough to bloody the nose of another leading light after they beat Bournemouth and drew with leaders Fulham.
And it came after West Brom, who could have briefly gone second with a win, had dominated the first half - only to waste chances.
Derby's prospective takeover by US businessman Chris Kirchner was called off on Christmas Eve, with the club's administrators saying an announcement on an alternative preferred bidder is "imminent".
The visitors, who had Ireland duo Robinson and Molumby in their starting 11, were gifted the first chance. A poor kick by Ryan Allsop saw Grady Diangana drive too close to the Derby keeper.
The Rams' first chance saw Ireland midfielder Knight let fly from 20 yards but his shot clipped a team-mate and sailed a few inches over the bar.
West Brom looked the more likely scorers, albeit mostly from set plays.
Jake Livermore's shot was deflected wide off Richard Stearman, Cedric Kipre slid in at the far post as Liam Thompson hacked clear but Allsop smothered after Conor Townsend flicked on Adam Reach's free-kick.
Reach headed straight at Allsop after Kyle Bartley headed Darnell Furlong's corner back into the danger area, then Allsop smothered Robinson's low shot after Livermore put the forward through.
Albion had the ball in the net in the 53rd minute when Reach's free-kick was flicked home by Kyle Bartley, but the offside flag went up immediately.
Derby, who also had Ireland Under-21 capEbosele in the starting side, made a double substitution in an effort to force the issue in the 57th minute as Kazim-Richards and Ravel Morrison replaced Luke Plange and Sam Baldock.
The changes had an immediate effect as the Rams made the decisive breakthrough in bizarre fashion a minute later.
Kipre nodded a high ball towards Johnstone, who had come out of the penalty area to deal with it. He headed it straight into the path of Kazim-Richards, who side-footed into the empty net from 25 yards.
Bartley sent a flicked header straight at Allsop from Furlong's long throw-in as Albion tried to hit back.
Matt Clarke had a golden chance to equalise when he was presented with an unmarked header from Kipre's cross - but he could only nod over the bar.
87' #DCFC 🐏 1-0 #WBA 🟡— Derby County (@dcfcofficial) December 27, 2021
Great shift, Festy! 👏 pic.twitter.com/UA7jp5ODDn
Substitute Jordan Hugill then wasted another chance for the Baggies when he side-footed wide from fellow sub Tom Fellows' cross.
Enniscorthy native Ebosele was withdrawn on 87 minutes with former Ireland Under-18 cap Eiran Cashin entering the fray.
In the dying seconds, Bartley's header was brilliantly tipped over by Allsop from Robinson's cross.
Elsewhere, Dominic Solanke's 18th goal of the season gave Bournemouth a 1-0 victory at QPR and put them top of the Championship.
It was the Cherries' first win in six matches and took them above promotion rivals Fulham while Rangers ended the match with 10 men after Andre Dozzell was sent off in the final moments.
Solanke struck four minutes before half-time after Sam Field was adjudged to have fouled Jefferson Lerma - a decision by referee Keith Stroud which incensed the home fans.
The resulting free-kick was swung in from the left by Junior Stanislas and Solanke flicked a header beyond Seny Dieng and into the far corner of the net.
Dundalk native and former Burnley centre-back Jimmy Dunne started for QPR, while Ireland senior international Mark Travers was in goal for Bournemouth.