Yousef Salech's goal was his 10th in 26 appearances since joining Cardiff in January, while Rubin Colwill has three in four games this season
Cardiff City's unbeaten start to life under Brian Barry-Murphy continued as they cruised to a 3-0 victory over Rotherham United.
Yousef Salech scored his first of the season to put Cardiff in front shortly before half-time and Rotherham never looked like producing a response.
Cian Ashford's classy finish doubled the home side's advantage and Rubin Colwill tapped home to wipe out any chance of a Rotherham revival.
Salech had the first opportunity of the afternoon but shot too close to Cameron Dawson, before Ollie Tanner's clever corner teed up David Turnbull only for the Scot's shot to roll wide.
Salech saw a decent penalty shout turned down after a tug from Zak Jules, but the towering Dane's moment came when he headed home Turnbull's corner at the far post.
Ashford exchanged passes with Turnbull before curling a left-footed shot high into the far corner as Cardiff assumed total control.
Jules was then made to pay for a loose pass as Ashford fed Salech and his low cross allowed Colwill – wearing the captain's armband with Calum Chambers only on the bench - to sweep in his third goal of the season.
Victory leaves the Bluebirds with seven points from three League One games following relegation from the Championship, but this was a second successive league defeat for Matt Hamshaw's disappointing Millers.
What was the main talking point?
Barry-Murphy fielded another young team, with three teenagers in the back four as academy product Dakarai Mafico was handed his debut on the left flank of the home defence.
In truth, it was a difficult day for 18-year-old Mafico, who was substituted 10 minutes before half-time amid home fears that he was one foul away from a red card after his booking for tripping Ar'jany Martha.
But Mafico – who played at left-back despite being better known as a midfielder – may yet get another opportunity soon, as giving youngsters a chance seems to be the way forward under Barry-Murphy.
The average age of Cardiff's starting side was just 22, but the shortage of experience did not matter against a Rotherham side who offered little going forward until substitute Marvin Kaleta drew a decent save from Nathan Trott four minutes from time.
By that stage, the contest was long since dead.
There will surely be tougher days than this to come for Cardiff, but the Welsh club are enjoying life right now having moved up to second in the early-season league table despite the fact that goalkeeper Trott is their only summer recruit to date.
Having dropped to 18th, Hamshaw will hope to have a number of influential players such as striker Sam Nombe, who was again absent through injury, back in the fold as quickly as possible.
Which players stood out?
Cian Ashford scored for the second successive game having scored in Cardiff's midweek EFL Cup win over Swindon
Cardiff took a little while to get going as an attacking force, but eventually their quality proved too much for Rotherham to handle.
Salech was a handful for Championship defences after moving to Wales in January and, now he is off the mark in 2025-26, the hope for Cardiff will be that the 23-year-old can produce a scoring streak.
Colwill has managed exactly that, after following up his two free-kicks with another goal to continue his fine start to the season, though it was Ashford who produced the goal of the day on this occasion.
What they said
Cardiff head coach Brian Barry-Murphy:
"We played really well throughout, particularly in the second half when I thought required us to play a little bit quicker to nullify the opponents' strengths and exposing their weaknesses.
"To score from a set-piece is very important, it's something we are very conscious of improving and making the players really value. It's a big moment for us.
"Cian's was a really good finish. To see him combine with David Turnbull and have that quality – that is very beneficial to us.
"The third goal was a mistake from Rotherham I think because of the intensity of our pressure. It was really good from us to force that error. Then the final pass from Yousef was unselfish and that was a big moment."
Rotherham manager Matt Hamshaw:
"First half the game plan was to try to contain them. I am disappointed with all three goals we concede but to concede from a soft set-piece is disappointing.
"There were a couple of key turning points in the game. Murph (Barry-Murphy) brings his left-back off after what could have potentially been a second yellow card.
"But it wasn't good enough second half. I was pleased with some aspects first half. I am well aware we are missing a few key players at the minute. We need to strengthen in some key areas.
"We are not scoring enough goals so as soon as a team gets a goal we are struggling a little bit."
What's next for both teams?
Cardiff are back in League One action on Tuesday when they travel to face AFC Wimbledon.
But Rotherham have no game in midweek after their fixture against Burton was postponed as a result of the Brewers' Carabao Cup tie at Tranmere having to be rearranged for Tuesday.
Therefore, the Millers will have a week to prepare for next Saturday's home league game against Wigan.
