Home debutant Fraizer Campbell scored both goals for Cardiff in their 1pm kick-off at home to Bristol City, opening the scoring moments before the half-time whistle before finding the target again after 58 minutes from close range.
A stoppage-time own goal from Ben Nugent denied the Bluebirds a clean sheet but they remain eight points clear of nearest challengers Hull, who beat Charlton 1-0 at the KC Stadium courtesy of Mohamed Gedo's goal following a mistake from Addicks goalkeeper Ben Hamer in the 33rd minute.
Watford kept up the pressure on the top two with a 4-0 hammering of free-falling Birmingham.
Troy Deeney scored twice for the Hornets, after 38 and 62 minutes, with Ikechi Anya (43) and Almen Adbi (89) also on target in a one-sided affair.
Watford are three points behind the Tigers and one ahead of Crystal Palace, who climbed to fourth with an easy 4-1 success over fellow play-off hopefuls Middlesbrough.
Glenn Murray fired Palace in front after nine minutes before second half goals from Peter Ramage and Murray again put the hosts into a commanding lead.
Faris Haroun replied for Boro 10 minutes from time but Kevin Phillips added more misery four minutes later.
Leicester drop two places to fifth having not played.
Ipswich, meanwhile, moved four points clear of the bottom three with a 1-0 win over Blackpool at Portman Road, Michael Chopra scoring the only goal with his left foot after 50 minutes.
Wolves on the other hand sit just a point above the relegation zone after playing out a goalless draw with Derby.
The points were also shared in the day's other game at the City Ground, where Craig Davies' 78th-minute strike earned Bolton a 1-1 draw with Nottingham Forest.