Johnny Russell made the perfect entrance to give Steve McClaren a winning start to his second spell as Derby manager as his side beat Leeds 1-0 at the iPro Stadium.
Russell smashed a low shot in from the edge of the area four minutes after coming on as a second half sub to earn Derby's first home championship victory of the season.
Leeds almost spoiled McClaren's return when sub Marcus Antonsson hit a post in stoppage time but Derby held on in front of a 31,000-plus crowd.
It was no surprise that McClaren switched to his favoured 4-3-3 formation but a long-range effort from Bradley Johnson that cleared the bar was as close as Derby came in a tepid opening 20 minutes.
Hadi Sacko almost went clear for Leeds before Jacob Butterfield fired over from 25 yards in the 26th minute but the visitors fashioned an opening a minute later when Luke Ayling crossed from the right and Chris Wood flashed a header wide.
Derby responded with a clever chip from Johnson that put Matej Vydra behind Leeds on the left but the striker's low shot fizzed just past Rob Green's far post.
Butterfield was off target with another effort from distance and Sacko was close to getting on the end of a Pablo Hernandez pass in the 42nd minute before a disappointing half ended with Kyle Bartley thumping a header against the bar from a Alex Mowatt corner.
Derby were forced into a change in the 52nd minute when Ikechi Anya limped off following a robust challenge from Bartley and his replacement Russell fired the home side ahead four minutes later.
A corner was only cleared as far as the edge of the box and Russell was the first to the loose ball and drove a low shot past Green for his first goal of the season.
Derby thought they had scored a second in the 68th minute when Tom Ince broke away down the right and his low cross was turned in by Vydra but the Czech striker had just strayed offside.
Leeds pressed hard for an equaliser and almost got it in the fifth minute of added time when Antonsson curled a right foot shot past Carson but the ball came back off a post.
Derby manager Steve McClaren:
"I think you could see the nervousness of the players but amongst that nervousness the players showed fight, the attitude was great and we got some great blocks in at the end.
"We worked our socks off and we needed that second goal and we have to learn that. The last 10 minutes was always going to be nervous but we rode our luck and got through it and it was a big three points.
Leeds head coach Garry Monk:
"I said to the players at half-time that we need to put our game on the pitch a little bit better and we came out and we started to do that and then we conceded a poor goal from our point of view which put us on the back foot.
"We had a go in the last 25 minutes and had a couple of chances but overall I think we didn't do enough of the things we have done really well in recent games with the ball to give ourselves the best chance of getting something."