Kenzo Goudmijn's goal was his second in as many games for Derby
Derby County secured their ninth successive home win to keep Cardiff City rooted to the bottom of the Championship.
Kenzo Goudmijn put the hosts ahead in the first half with a fine first-time finish from Callum Elder’s cross.
Derby had chances to extend their lead but were thwarted by Cardiff goalkeeper Jak Alnwick.
Substitute Ollie Tanner wasted the Bluebirds’ best opportunity after the break as he blazed over, before Ebou Adams somehow failed to score Derby's second in injury time as he missed with an open goal.
Derby’s third win from three home games this season – and ninth on the bounce including their previous campaign in League One – lifts them to eighth in the Championship table.
Cardiff, meanwhile, remain winless at the bottom as a fourth defeat leaves them with just one point and a single goal from five games.
This latest loss came despite manager Erol Bulut’s attempt to shake things up with six changes to the Cardiff team beaten by Middlesbrough before the international break.
One of those recalled, attacking midfielder Rubin Colwill, had the visitors’ first chance as he shot straight at Jacob Widdel Zetterstrom.
The game started at a rapid pace and, as Derby broke after Colwill’s effort, Goudmijn’s shot was well blocked by covering Cardiff defender Joel Bagan.
The Dutch midfielder opened the scoring with his next effort, smartly turning in a typically excellent cross from Callum Elder.
Cardiff rallied as Dimitrios Goutas and Callum O’Dowda both had headers kept out by Zettterstrom, before ex-Bluebirds winger and now Derby captain Nathaniel Mendez-Laing forced Alnwick into a superb save.
Mendez-Laing continued to threaten in the second half, while Kayden Jackson was denied by Alnwick.
Cardiff struggled to create chances but Tanner did have an opening, only to shoot over the bar.
The visitors threw everyone forward in the closing stages in an attempt to snatch just a second point of the season but could not find a way past Derby’s defence.
Former Cardiff midfielder Adams had a glorious chance to add to Derby’s lead in added time but, with Alnwick out of his goal, the Gambia international somehow missed.
It did not affect the result as Derby held on for a third win of the season to compound a miserable start to the campaign for Bulut and Cardiff.
Post-match reaction
Derby head coach Paul Warne told BBC Radio Derby:
“I thought our play deserved possibly a second goal we didn’t get. To come away with a 1-0 win is still great, another clean sheet.
“The lads are giving everything they can so, even if we’d conceded late on, it wouldn’t have detracted from my pride in the group.
“They gave everything they could physically and got their win based on that.”
Cardiff assistant coach Omer Riza told BBC Sport Wales:
“We’ve had a few disappointing afternoons. We knew it was going to be a tough game but we wanted to control the game.
“We needed to stop leaking goals but we’ve done it again. From nothing, we’ve conceded a goal from a throw-in, a scrappy goal, it puts us on the back foot and we’re chasing the game.
“We need to do more. Football’s about chances and scoring goals and it can put you on the back foot when you don’t do that.
“When you talk about concern, obviously we’ve lost games and we’ve picked up one point so it’s not where we want to be.”
