The Iron extended their unbeaten run to six matches, but had to settle for a point against Chesterfield.
Paddy Madden gave United the lead, but Jamal Campbell-Ryce came off the bench to earn the visitors a 1-1 draw at Glanford Park.
The result means that the Iron are now six points off the play-offs heading into the final nine games of the campaign.
Elsewhere in League One, Burton continued their march towards promotion as they beat play-off hopefuls Port Vale 4-0.
Goals from Lucas Akins, Mark Duffy, Calum Butcher and an Anthony Grant own goal secured a comprehensive victory for the leaders.
Wigan kept the pressure up though as Haris Vuckic grabbed the only goal as they beat seventh placed Bradford, extending their unbeaten run to 16 games.
They are above Walsall on goal difference, with the Saddlers producing a dramatic turnaround to beat bottom side Colchester 2-1.
Alex Gilbey gave the visitors the lead, but two goals in the final few minutes from Tom Bradshaw and Matt Preston ensured they kept the pressure up on the top two.
Gillingham lost ground on the automatic places though as they were held to a 1-1 draw at Southend, with Luke Norris cancelling out Anthony Wordsworth’s opener for the hosts.
Millwall continued their excellent form, with Chris Taylor’s second minute strike proving to be enough to defeat Sheffield United.
The Lions have now only lost one in their last 13, which has taken them to within six points of the League One top two.
Barnsley moved back into the final play-off spot as they enjoyed a comfortable 2-0 win at Fleetwood, their fourth win in five.
An own goal from Joe Davis put them ahead, before Josh Scowen doubled their advantage in the final ten minutes.
At the bottom, Crewe missed a great chance to boost their survival prospects as they slipped to a 2-1 defeat to ten-man Blackpool, missing a late penalty too.
Jack Redshaw gave Pool the lead, but was dismissed. Marcus Haber looked to have grabbed Crewe a point, only for Tom Aldred to net the winner.
Oldham missed the opportunity to climb out of the bottom four, losing a five goal thriller to local rivals Rochdale.
Aaron Amadi-Holloway grabbed a brace, but it was not enough as Ian Henderson, Callum Camps and an Anthony Gerrard own goal secured the visitors’ victory.
The final spot is occupied by Doncaster as they slipped to another defeat, with Peterborough striking late to win 2-1.
James Coppinger gave them the lead, but Aaron Williams levelled before Ricardo Santos grabbed an injury time winner for Posh.
Elsewhere, Bury came from behind twice to secure a 2-2 draw with Shrewsbury. Tom Soares and Peter Clarke cancelled out Sullay Kaikai’s brace.
Coventry and Swindon shared the points following their goalless draw, meaning the Sky Blues missed the chance to jump into the top six.
Next up for the Iron is a trip to Barnsley on Good Friday, with Nick Daws’ side looking to keep up their good form and push for the top six.