Midfielder Neil Danns scored the only goal of the game after just 16 minutes as he capitalised on superb build-up work from Lloyd Dyer.
Southampton have taken the lead in the English Championship with a 3-0 victory over Watford. Rickie Lambert took his goal tally to 21 for the season across all competitions with a hat-trick against Watford.
West Ham drew at home. Sam Allardyce's team were held to a goalless draw by Crystal Palace in the early game on Saturday.
Third-placed Reading also made up ground with a 2-0 victory over Middlesbrough.
Noel Hunt gave Reading the lead after 17 minutes, before a classic free-kick from Ian Harte with 10 minutes to go completed the win to leave Reading four points behind West Ham.
Blackpool were the other club in the Championship's top six that won on Saturday, beating Bristol City 3-1.
Thomas Ince scored twice, while Kevin Phillips grabbed a late third goal for Blackpool as the visitors came from 1-0 down at half-time to win.
Blackpool moved above Birmingham, who lost 2-1 at home to Nottingham Forest, while the other club in the top six, Cardiff, will not play this weekend due to their involvement in the Carling Cup Final on Sunday.
In other results, Brighton beat Ipswich 3-0. C. Mackail-Smith scored, while Ashley Barnes net twice.
Millwall won 3-1 in Burnley. Andrew Keogh, Josh Wright & Harry Kane scored for the visitors. Jay Rodriguez scored the consolation goal for Burnley before end of full-time through his penalty goal.
Coventry defeated Barnsley 1-0. Clive Platt scored a late winning goal for Coventry.
Doncaster and Peterborough drew 1-1. Giles Barnes scored first before the end of the first-half. But Tyrone Barnett equalize with a late goal.
The match between Leeds United and Portsmouth ended scoreless.
