Substitute Paik Seung-ho's first goal of the season helped Birmingham City complete a comeback win against a Derby County side whose injury crisis was deepened in defeat.

Blues had a number of chances to make their victory more comfortable, with Luis Vazquez guilty of an extraordinary late miss as his attempted finish from two yards out in front of a unguarded net went over the bar.

Paik's headed winner came after Derby forward Henrik Meister left the field on a stretcher in concerning scenes for John Eustace's Rams, who are already without a long list of senior players.

Bobby Clark had put the Rams ahead in the first half, beating Blues goalkeeper James Beadle at his near post with a fierce angled shot.

Carlos Vicente was quick to restore parity when he headed in before the break and, despite Derby immediately looking more likely to score after losing Meister, Paik came off the bench to claim all three points for the visitors.

With Derby dealing with early season injury woes, which only last week included a list of eight senior players, the return of last season's leading scorer Carlton Morris was a timely one for a side that has stuttered in front of goal this term.

But even with the former Luton Town and Barnsley striker back, the Rams struggled to create a meaningful chance before his knockdown header in the box allowed Sam Szmodics to slip a clever pass to Clark, who then slammed home from a tight angle in the 40th minute.

Birmingham had squandered a number of chances to take the lead themselves, with August Priske glancing an early header over and Vicente wastefully curling an effort wide, while Jay Stansfield had a goalbound effort blocked by Sondre Langas and Tomoki Iwata flashed a first-time effort just off target.

Vicente, however, was clinical when he beat Rams left-back Charlie Taylor to a searching Millar cross at the back post to nod Blues level just two minutes after going behind.

The injury to Meister, who had been lively on what was his first start at home since joing the Rams on loan from Italian side Pisa, was a blow that Derby were intent on quickly bouncing back from with Mohammed Fuseini forcing Beadle to make a save at full stetch before Eiran Cashin directed a close-range attempt just wide.

At the other end, Derby goalkeeper Jacob Widell Zetterstrom argued he had been fouled when he failed to judge the flight a Millar corner which allowed Paik to nod in from point-blank range.

Zetterstrom went on to deny Vicente and Stansfield in quick succession to ensure the Rams remained in the game, which Vazquez's horrendous miss also helped with as Derby piled forward in search of a late equaliser - which Birmingham's Christoph Klarer denied them by blocking a Szmodics shot on the line in stoppage time.

When Meister went down near the halfway line it was not immediately clear what the issue was.

But Pride Park was soon in hushed silence as the Dane received lengthy treatment from medics before eventually being carried from the pitch.

Meister is seen by the recruitment team at Derby as a player capable of emulating Patrick Agyemang, who made a huge impact on his arrival from Major League Soccer last season, but instead he now joins the United States international in a treatment room that already includes Matt Clarke, Derry Murkin, Filip Bilbija, Rhian Brewster, Craig Forsyth and Lewis Travis.

And while the defeat against Birmingham leaves Derby winless at home in the league and in the bottom three, the real cost of the loss is not yet clear.

For Blues, victory eases the pressure on boss Chris Davies after their unbeaten start was ended at Norwich in midweek.

Derby County head coach John Eustace told BBC Radio Derby:

"It was a game we certainly didn't deserve to lose. They were two real soft goals and when you concede goals like that you are not going to be on the right end of the results that you want.

"The effort was amazing again today, I thought we played some really exciting stuff and it was great to see the new players impact the game as well, so we are really disappointed to lose.

"The lads have been as good as they can, they have been working as hard as they can. We are obviously missing the player of the year from last year [Matt Clarke], who is a quality centre-half, and we haven't been able to have a structured starting XI and the back four are chopping and changing a lot. Until we get a stable team and stable back four we are always probably going to get issues.

On Henrik Meister injury: "He's not well. It's a big blow when you come off after 50 minutes after playing well. He's having his concussion protocols so we'll just have to see how he is. I was speaking to him and he seems ok."

Birmingham City manager Chris Davies told BBC Radio WM:

"It was a game that had a bit of everything. I thought we were well worth the win and I thought we could have been a couple of goals up in the game.

"Against the run of play it was a sloppy goal and we gave ourselves a bit of a challenge there.

"It was good to get the goal before half-time and after scoring the second goal, the determination, grit and mentality to defend the goal and be a team and grind out a win was the most pleasing thing of all."