Zian Flemming's early free-kick was enough for Millwall to defeat Watford 1-0 at The Den and make it two wins from two since manager Neil Harris' return to the club.
Leicester's lead at the top of the Championship has been cut to just three points with 11 games to go after relegation-threatened QPR claimed a surprise 2-1 victory.
Joe Aribo struck at the death to seal stuttering Sky Bet Championship promotion hopefuls Southampton a dramatic, much-needed 4-3 victory away to 10-man Birmingham.
Ipswich moved back up to second place in the Sky Bet Championship following a 2-0 win at Plymouth.
Leeds missed the chance to crank up the pressure on leaders Leicester as they were held to a 1-1 Yorkshire derby draw at Huddersfield.
Ipswich chalked up a fourth successive win to keep up the pressure at the top of the Sky Bet Championship with a 3-1 win over Birmingham.
Cardiff ended their six-game winless run at home with a 2-1 Championship victory over relegation-threatened Stoke.
Japhet Tanganga and Zian Flemming gave Neil Harris the perfect start to his fourth spell at Millwall as they upset Southampton 2-1 at St Mary's.
An Ike Ugbo double in the first half was enough to give 10-man Sheffield Wednesday a huge 2-1 Sky Bet Championship victory over Bristol City at Hillsborough.