Reading's run of four straight league victories was ended by Cardiff City's eighth home win of the season this afternoon.
All the goals came in the opening period, with Joe Mason, Aron Gunnarsson and Kenny Miller striking for the hosts.
Mason put the Bluebirds ahead in the 13th minute after being set up by Miller before Peter Whittingham swung over a corner for Gunnarsson to power a header home.
It was three nine minutes before the break when Miller poked home from close range.
The visitors were given hope for the second-half, when they have scored almost all of their goals this season, when Jobi McAnuff followed up Jimmy Kebe's parried effort.
Brian McDermott's men were unable to mount a comeback in the second half as Cardiff saw out the game to move up to third in the Championship.
The Welsh side are now two points adrift of the joint leaders Southampton and West Ham while Reading remain fifth.
