A stunning Wayne Rooney free-kick was enough to see Derby past play-off rivals Preston as they earned a 1-0 win at Deepdale on Wednesday evening.
England's record goalscorer struck the winner after 18 minutes, beating North End goalkeeper Declan Rudd an with inch-perfect free-kick from just outside the penalty area, following a foul on Louie Sibley.
There was a vast improvement from the hosts after the break, but there was nothing Alex Neil's men could do to halt a Rams' upturn that has seen them climb the table after just three defeats in their past 15 outings.
Derby are now just a point outside the Championship play-off places on 60 points, while Preston - who became the first English club to reach the 5,000 league game milestone - trail them by three points with just six games left to play.
How Wayne Rooney made the difference for Derby once more
Despite being an intriguing match-up between two sides with an outside chance in the race to reach the play-offs, there was only one team in the game at the halfway stage in Lancashire.
Preston - who were lacking creativity with Daniel Johnson out injured - were forced to quieten a determined Martyn Waghorn but found themselves chasing the game when referee Jarred Gillett awarded a free-kick after Paul Huntington's foul on Sibley. The Australian did, however, appear to miss the North End defender's apparent stamp on the youngster after he went to ground.
Rooney then bent the ball up and over the wall so expertly that goalkeeper Rudd was rooted to the spot.
Duane Holmes then saw an arrowed shot saved, yet the Rams were content to sit on their slender advantage and defend in numbers in order to stifle their hosts' rare advances.
The restart saw a marked improvement from Preston, just not in the final third, which led Neil to sacrifice the stability brought by the presence of Paul Gallagher and Ben Pearson in favour of the firepower of Jayden Stockley, Sean Maguire and Tom Barkhuizen.
And the latter pair almost linked up in the third minute of second-half stoppage-time, but Barkhuizen opted to shoot from a tight angle on the byline, in spite of his team-mate standing in space inside the penalty area.
What the managers said...
Preston's Alex Neil: "I think, for our second-half efforts, we deserved something. Derby had a couple of good chances in the game but the one Brad Potts cut back for Alan Browne was good for us, too.
"It's damaging and I can't get away from that. We're all really disappointed with how the games have panned out. At this level, it's fine margins and, at the moment, we're finding ourselves on the wrong side of those margins."
Derby's Phillip Cocu: "It was a very important win and it was a good game today. Both teams tried to play with a lot of energy and at a high intensity but in the end a great goal gave us the win.
"We have some very tough games coming up but they are also great challenges for us. We have to show that we've developed against the bigger teams but there are still a lot of games to play and I'm just happy with this win."
Derby face Nottingham Forest in the East Midlands derby on Saturday, live on Sky Sports Football, with kick-off at 12.30pm. Preston, meanwhile, travel to relegation-threatened Huddersfield later on at 3pm.