The visitors had made the stronger start and Blues keeper Connal Trueman was forced to produce a diving save to deny Andrew Dales. With five minutes played Dylan Hayes headed wide for the Rams with the goal at his mercy.
But having escaped with their goal intact, Blues grew into the encounter and started putting pressure on the visitors' defence.
Trialist Angelo Balanta saw his powerful effort tipped over the bar. Brown then beat the offside trap, but his close-range shot was smothered by Kelle Roos in the Derby net.
Blues came desperately close to taking the lead after Balanta met Howard's corner with a header, but with the ball heading towards the back of the net it was cleared off the line by Hayes.
The hosts finally got the goal that their play deserved after 42 minutes when they were awarded a penalty after Reece Brown was upended by Ayrton Wassell just inside the area
Howard, who was making his first competitive start in several weeks, following an ankle injury, stepped up to take the spot-kick and made no mistake as he sent the keeper the wrong way.
The second-half failed to live up to the first, with chances at a premium and both sides.
Other than a handful of long-range efforts neither keeper was really tested and Blues held on for a deserved victory.
Coach Karl Hooper felt that his side warranted their victory.
“It was a deserved win and I think the stats would show we had a lot more possession,” he said.
“We started a little bit slowly and gave them a couple of chances in the first five minutes, but then went on to dominate possession throughout the game.
“Our better chances came in the first half when we had one cleared off the line, a couple of shots that were blocked that looked certain goals and the their keeper has also pulled off a brilliant save.
“In the second half we were more progressive, but for the amount of play we had we could have created a few more goalscoring opportunities with a better final ball or been a bit cleverer movement in the final third. Overall though, it was very pleasing.”
The game also allowed Bryan Howard game time following his return from injury and Hooper felt the midfielder led by example.
“Brian was a great example to the young lads with his professionalism,” added Hooper. “His composure on the ball rubbed off on those around him.”
Trueman, Dacres-Cogley, Ferguson, Brown, Fry, Bell, Balanta (Hales. h/t), Howard, McGee (Bernard, 62), Rusnak, Gray.
Subs not used: Webb, Weaver, Truslove.