Derby secured their first win of the season with a 2-0 victory at Portsmouth thanks to goals from Sammie Szmodics and Lars-Jorgen Salvesen.
Pompey dominated possession and had 19 shots to the Rams seven, but Josh Eustace's side were ruthless when it counted and deservedly left the south coast with three points.
Derby took the lead with their first meaningful attack in the 16th minute after an excellent run down the right from Bobby Clark saw him pull the ball back to Szmodics, who cleverly spun his defender and fired low into the near post.
Portsmouth were bossing possession and territory and Abu Kamara was screaming for a penalty when he tumbled under the challenge of Charlie Taylor, but referee Sam Allison ruled the Rams defender had played the ball.
John Mousinho handed a first start to Serbian striker Marko Milovanovic after the former Almeria player scored a late consolation penalty in Saturday's 2-1 defeat at Bristol City.
The six-foot five-inch forward was lively in the early stages and saw a low shot from the edge of the area comfortably saved by Jacob Widell Zetterstrom in the Derby goal.
But though they had 64 per cent of possession and 10 shots in the first half, that was Pompey's only effort on target.
Derby enjoyed a good spell of pressure at the start of the second half and the ebullient Clark put in a low cross which reached Sondre Langas on the edge of the six-yard box but the Norwegian was unable to get his shot away.
Pompey then came close to a fortuitous equaliser when Zak Swanson swung in a cross which almost caught out Zetterstrom at the far post before he clawed it behind.
From the resulting corner, Kamara saw his effort deflected narrowly wide of the Derby post.
But as Mousinho's men continued to push forward, gaps were appearing for Derby at the other end.
Derby boss Eustace had just brought on Salvesen for Rhian Brewster and with almost his first touch, the Norwegian scored his first goal since January as he received the ball from Oscar Fraulo and smashed it into the top corner from the edge of the area with his left foot.
The excellent Clark was continuing to cause problems and almost added a third as his teasing run from the left ended with a low shot that flashed just past the post.
Pompey have now lost both of their home games and, for all their pressure, Mousinho will be concerned that his side look so toothless in attack.
Portsmouth's John Mousinho:
"We were really sloppy with some of the things that we did. We gave the ball away too easily and it ended in us conceding the second goal on a counter-attack again and not being able to get back in the game.
"We created a couple of half chances. We had some set pieces and I think the first attack Derby had and the only shot in the first half ends up in the back of the net. We have to be a lot better at coping with those specific moments and also coping with disappointment.
"I thought we reacted okay in the first half, but the second half, I didn't think we came out with any energy and any lively parts of our play."
Derby's John Eustace:
"It's just about keeping your head, keeping your nerve, not getting carried away with all the noise and the distractions which come with it when you don't win games and you don't perform very well.
"We haven't been able to play a starting XI on any of our pre-season games or in any of our first three games.
"So, it's just about doing the right things, believing in what you do and believing in the process. And that's something I've always done over the course of my managing career and something I believe works.
"We're delighted to get our first three points of the season, but nothing's ever decided in the first month or two months. Last year we won one of our first 10 games and then we were 45 minutes away from finishing the play-offs. So, let's just keep believing in what we're doing."
