Cardiff took over at the top of the Championship thanks to a 4-2 win at Scunthorpe as previous leaders QPR were held to a goalless draw at Nottingham Forest.
Jay Bothroyd gave the Bluebirds a perfect start in the second minute. He then turned provider as his cross found Michael Chopra who finished from close range.
Craig Bellamy’s free-kick was met by Bothroyd, who grabbed his 15th goal of the season in the 34th minute, although Kevin McDonald grabbed one back for the Iron on the stroke of half-time.
Dany N’Guessan added a second for the hosts but Seyi Olofinjana made sure for Cardiff with a fourth goal 11 minutes from time.