Lee Gregory scored on his home debut to put Derby on course for a much-needed 2-1 Championship victory over Middlesbrough whose play-off hopes suffered another blow.
Gregory marked his first Pride Park appearance following his loan move from Stoke by heading home the opening goal and he set-up Colin Kazim-Richards for a spectacular second.
Neeskens Kebano gave Boro hope before half-time but Derby stood firm in the second period to secure a victory that boosts their chances of staying up.
Wayne Rooney was looking for a response after Derby's late collapse in their previous game at Rotherham and he got it when his team went ahead in the 15th minute.
Middlesbrough were taken by surprise when Martyn Waghorn swung a corner beyond the back post where Lee Buchanan glanced the ball across for Gregory to head past Marcus Bettinelli.
Gregory was close to adding a second in the 24th minute when he sent a header narrowly wide with the visitors struggling to make an impact on another bitterly cold afternoon.
Sam Morsy tried to fire Middlesbrough up with a shot from just outside the box that fizzed over David Marshall's crossbar but Derby struck again in stunning fashion in the 32nd minute.
The ball was played quickly up the right and Gregory laid it off to Kazim-Richards who thumped a 25-yard shot that went in off the underside of the crossbar.
But the striker was at fault six minutes later when he lost the ball to Marc Bola who surged into the box and when Derby failed to deal with his low cross, Kebano drove the loose ball past Marshall.
It had given Boro hope for the second half but it was Derby who threatened after the break with Gregory crossing to Kazim-Richards who headed a chance over from 12 yards.
Duncan Watmore raced onto a long ball but could not pick out a red shirt and Anfernee Dijksteel was booked when he brought down Kamil Jozwiak before he could break into the box.
Derby were being pushed back but they almost caught their opponents on the break in the 72nd minute but Jozwiak stumbled on the edge of the area and the ball went through to Bettinelli.
The home side were defending well and for all their possession, Boro had not created a clear chance since Kebano's goal.
That changed in the 87th minute when a cross from the left dropped invitingly to Nathaniel Mendez-Laing 10 yards out but his low shot was blocked.
There was a scare for Derby in stoppage time when Bola swerved past two defenders before going over but his penalty claims were dismissed and the hosts held on for maximum points.
What the managers said...
Derby's Wayne Rooney: "It was a big win for us, coming off defeat in our previous game (against Rotherham). We felt it was better today to go two strikers and go a bit more direct and I thought we did that really well. Second half, certainly in the last 10 minutes, we gave away some sloppy free-kicks and we need to get better. It cost us against Sheffield Wednesday and cost us against Rotherham so our game management in those situations needs to be better.
"It's pleasing to get the two strikers on the score sheet and in the last 10 minutes, I thought the way we defended the box and put bodies on the line showed the character of this group. I think it's clear for everyone to see, the one thing this team has is character and great togetherness."
Middlesbrough's Neil Warnock: "It's disappointing result-wise but once again I didn't think we were a threat. Since I've been here, well in fact for the last few years really, there's not been enough threat up front.
"I thought last week if we'd had (Ivan) Toney we'd have won the game and I think if we'd had (Colin) Kazim-Richards today we would have won the game. I don't think there's much wrong that needs putting right but at the moment things aren't dropping for us either."