A super four-goal salvo gave the Bluebirds a resounding victory over high-flying West Ham.
Strikes from Alan Lee, Joe Ledley, Paul Parry and Jobi McAnuff gave City a well-deserved victory over a Hammers side that struggled to keep up with the pace of the new-look Bluebirds.
For 17-year-old Ledley, it was his first senior goal while McAnuff opened his City account by scoring against his former club.
It was same again for City, as Lennie Lawrence kept faith with the side that drew with Leicester at the weekend. The Hammers had Welsh international Carl Fletcher in a strong midfield.
One-time City target Luke Chadwick hit a crisp shot over the bar in the second minute but the Bluebirds went straight up the other end to open the scoring.
Hayden Mullins was dispossessed by Parry who went to the byline before squaring the ball to Lee, who slotted home at the far post.
City doubled their lead in the 15th minute when Ledley found the net. McAnuff flighted over a cross, the youngster brought it down before turning Hammers defender Tomas Repka, and firing home.
Cardiff almost added another goal on the half-hour when McAnuff was brought down just outside the area. Gary O'Neil's cleverly flighted free-kick struck the woodwork before being cleared by the over-worked visitors defence.
A Fletcher corner spelt danger for the hosts, and O'Neil made a goal-line clearance, but Matthew Etherington sent the ball back in only for City skipper Graham Kavanagh to head clear.
McAnuff was relishing playing against his former club, and a darting run in the 50th minute earned a corner, but Lee's header was safely gathered by the keeper.
Alan Pardew brought on Don Hutchison for the ineffective Chadwick a minute later, but City put the game beyond the visitors with a superb strike from Parry in the 54th minute.
Lee threaded a ball through and the former Hereford man slotted in at the far post beyond the diving Stephen Bywater.
As the Londoners pushed forward, City gave away too many free-kicks and this kept them pinned back in their own half for several minutes.
Midway through the second half, Marlon Harewood dashed down the right flank before cutting inside where he was upended by Kavanagh. Harewood picked himself up and fired the spot-kick into the corner of the net.
Pardew decided to go for broke by taking off defender Mullins and brining on Sergei Rebrov in the 73rd minute, but back roared the Bluebirds and O'Neil and Parry combined, before McAnuff turned the ball in at the near post to make it the heaviest defeat of the season for the visitors.