Southampton manager Nigel Adkins backed Tadanari Lee to fire his side towards promotion as the Japan striker scored his first goal for the club in a 4-0 demolition of Derby.
Lee joined the Championship leaders from Sanfrecce Hiroshima on a free transfer in January and he finally broke his duck for Adkins' team in his fifth appearance.
The 26-year-old struck in the 75th minute after goals from Jos Hooiveld, Aaron Martin, Adam Lallana had put Southampton firmly in control at St Mary's.
Southampton's emphatic victory moved them two points clear of second placed West Ham, although the Hammers have two games in hand in the race for promotion to the Premier League.
Hooiveld put Southampton in front from a corner and they doubled their lead 12 minutes after half-time when Martin finished from close range after another corner.
Daniel Fox completed his hat-trick of assists by teeing up Lallana's goal in the 65th minute and Lee then scored his first goal in English football with a spectacular long-range effort as Saints extended their unbeaten run in the league to five games.
"Tadanari Lee -- what a fantastic goal. He has come in from a different continent and has settled so well," Adkins said.
"He has applied himself in the right manner, is a really nice person, works really hard and is a talented, talented player. I think there is a lot more to come from him."
Cardiff boss Malky Mackay denied his players were distracted by next week's League Cup final against Liverpool after they crashed to a 3-0 defeat at Ipswich.
With West Ham not playing due to Blackpool's participation in the FA Cup, fourth placed Cardiff had a chance to close the gap, but they were swept aside.
The Bluebirds, who face Liverpool at Wembley on February 26, remain four points behind West Ham as Lee Martin scored twice either side of a Michael Chopra strike.
Yet Mackay said: "They're a very focused, hard-working group of players with no egos.
"They've focused on everything we've asked them to do all season and that was the case here."
Leeds striker Luciano Becchio fired a dramatic winner nine minutes into stoppage-time as Leeds came from two goals down to beat Doncaster 3-2 and give new manager Neil Warnock the perfect welcome to Elland Road.
Former QPR boss Warnock was appointed on an 18-month deal on Saturday after a meeting with owner Ken Bates in Monaco and, although temporary manager Neil Redfearn picked the side, Warnock spoke to his players before kick-off and also at half-time.
Warnock looked set for a miserable start as Mamadou Bagayoko scored in the 32nd and 54th minutes to put bottom of the table Doncaster in control.
But Andros Townsend reduced the deficit in the 55th minute and Adam Clayton equalised in the 80th minute before Becchio's late intervention sealed the points.
Crisis-club Portsmouth slumped into the relegation zone as a dismal week ended with a 2-0 defeat at Barnsley.
Just over 24 hours after entering administration for a second time in two years, debt-ridden Pompey had striker Dave Kitson sent off in the first half before goals in the last 15 minutes from Jim O'Brien and Matt Done consigned them to defeat.
Nottingham Forest took advantage of Portsmouth's woes to climb out of the bottom three with a 2-0 win over fellow strugglers Coventry at the City Ground.
Elsewhere, Peterborough defeated Bristol City 3-0, while Crystal Palace crushed Watford 4-0.