Chelsea came back firing after the international break with a big win, but took a little while to settle into Saturday's match against Neil Warnock's men.
Cardiff took good advantage of the situation with a smart set-piece routine resulting in the opening goal for Sol Bamba, but were swiftly pegged back - and ultimately destroyed - by Eden Hazard.
The Belgian twice linked up with Olivier Giroud to score a first-half brace to put the game beyond the Welsh side, completing his hat-trick from the penalty spot after the break.
Willian put the icing on the cake for Chelsea towards the end of the 90 minutes with a sumptuous strike that the Neil Etheridge could do nothing about.