Scunthorpe boss Alan Knill saluted a "massive win" after they beat relegation rivals Crystal Palace 2-1.
Goals in each half from David Mirfin and Ramon Nunez settled a real six-pointer at Selhurst Park as United closed the gap on the fourth-bottom Eagles to just three.
Sean Scannell pulled one back but was later sent off along with Scunthorpe's Joe Garner as tempers began to fray, but it could not take the shine off the result for Knill.
"It's a massive win," he admitted. "It was billed as a must-win game and it really was.
"If they had gone nine points in front it would have been difficult with four games left. We've cut it to three and it gives us a belief that we can still do it.
"We are always on at the them that they are better than they have shown. From start to finish it was a really good performance by the team."