Coca-Cola Championship leaders Wolves continued their return to form with a scrappy win at Sheffield Wednesday.
The only goal of the game came in the fifth minute, Sylvan Ebanks-Blake left unmarked to head in Michael Kightly's cross to give Mick McCarthy's side their second 1-0 win of the week.
Birmingham kept up the pressure in second with victory at Southampton, Keith Fahey scoring the winner in first half injury time.
But Reading fell further behind the top two after drawing 2-2 at Plymouth. Paul Gallagher scored his fifth goal in four games to give the hosts the lead on 20 minutes but Reading equalised within two minutes through defender Alan Pearce.
Worryingly for Argyle, top scorer Gallagher had to be replaced at half-time with an injury but Jimmy Mackie soon cheered up the home fans with a stunning strike after 56 minutes to put Paul Sturrock's men back in front.
The Royals restored parity with 10 minutes to go through Jimmy Kebe but will view the result as two points dropped in the increasingly fraught battle for promotion.
Steve Coppell's team have now won only once in six games and are only four points ahead of Cardiff, having played a game more.
The Bluebirds halted Doncaster's run of good form with a 3-0 win at Ninian Park, secured thanks to strikes from Michael Chopra (10), Jay Bothroyd (29) and Eddie Johnson (60). With three games in hand over the top two, a winning run would give Dave Jones' team a realistic chance of making automatic promotion. They move ahead of Sheffield United on goal difference, the Blades drawing 0-0 at QPR.
Preston failed to take advantage of Burnley's weekend off in the FA Cup, succumbing to a 2-1 defeat at Crystal Palace which leaves them only a point ahead of the Clarets in sixth.
Billy Jones gave North End the lead on the half hour, but two strikes in quick succession from Anthony Stokes (32) and Neil Danns (34) wrapped up the points for the Eagles.
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