Jamie Cureton's second goal in as many home games helped Swindon overcome Walsall at the County Ground and drag the Saddlers into relegation trouble - the Robins are now just two points behind United.
Former Reading striker Cureton delivered an unstoppable volley two minutes before the interval to give the Robins their second consecutive home win.
The 1-0 scoreline somewhat flattered Walsall, who were poor throughout and Paul Merson's side now face a real relegation scrap.
Izale McLeod's early header secured a vital win for MK Dons against fallen giants Nottingham Forest to breath fresh life into their bid to avoid the drop in front of the biggest crowd of the season at the National Hockey Stadium.
McLeod pounced from close range in the 22nd minute to seal the rock-bottom Dons' first win in 11 league games in front of 7,670 fans.
The franchise outfit now have 27 points, six behind Scunthorpe, ahead of Saturday's crunch six-pointer at Glanford Park.
Ten-man Gillingham made a mockery of their recent travel sickness to pull off an impressive 2-1 win at Swansea City, and put a five point cushion between them and the bottom four.
Darren Byfield and Neil Harris struck in either half to record the Gills' first away win of the campaign.
Andy Robinson did mange to pull one back from the penalty spot after Mike Flynn was sent off for the visitors but it was too little, too late.