Joe Bennett’s late header secured a dramatic victory over Rotherham United in the South Yorkshire snow.
Sheyi Ojo had put the visitors ahead, but after Matt Crooks' equaliser, Bennett’s winner clinched successive City wins.
The Bluebirds enjoyed a bright start at the New York Stadium, with Ojo and Kieffer Moore combining well early on.
One such move created space on the left for Bennett to fire in a dangerous cross, which Freddie Ladapo did well to head clear.
Having held off some early pressure, the hosts soon settled into the contest and began to create opportunities of their own.
Curtis Nelson timed his tackle on Matt Crooks perfectly to snuff out one attack, while Michael Smith twice tested Dillon Phillips, who made two fine stops at full stretch to deny him.
Rotherham stopper Viktor Johansson was next called into action at the other end to smother Moore’s low drive.
But minutes before the break, the Bluebirds broke to take a lead into the interval.
After battling superbly at the back, Harry Wilson picked up a loose ball and slid Ojo through on the halfway line. The winger showed excellent composure to race towards goal unopposed and slot into the bottom corner.
A stunning save from Johansson kept the Bluebirds from doubling their lead at the start of the second half. Sean Morrison took the ball down in the box and rifled it goalwards, only for the ‘keeper to palm wide.
But Rotherham took advantage to equalise as Smith’s inch-perfect cross was turned home at close range by Matt Crooks.
Second-half substitute Josh Murphy came close to an instant response as he brought the ball down in the box and fired over.
As the match entered its finale, conditions deteriorated quickly at the New York Stadium, with heavy snow calling for the change to a yellow ball.
But the weather didn’t deter the Bluebirds, who continued to press and secure a dramatic winner five minutes from time.
Murphy’s superb left-footed cross found the on-rushing Bennett, who headed home at the back post to clinch a second successive victory.
Rotherham United: Johansson, Olosunde (Giles 71), Ihiekwe, Wood (Hirst 87), Robertson, Harding, Barlaser (Ladapo 81), Wiles, Wing, Crooks, Smith.
Subs not used: Vickers, A. MacDonald, Clarke, S. MacDonald, Sadlier, Jozefzoon, Hirst.
Cardiff City: Phillips, Ng, Morrison, Flint, Nelson, Bennett, Vaulks, Ralls (Pack 63), Wilson, Ojo (Murphy 53), Moore.
Subs not used: Ratcliffe, Brown, Bagan, Sang, Hoilett, Harris, Watters.