Scunthorpe moved out of the League One relegation zone at the expense of fellow strugglers Colchester United, who suffered a ninth successive loss.
Dominic Samuel and Gavin Massey both went close for the U's early on, while home keeper Mark Cousins denied Akpo Sodje, Jimmy Ryan and Andy Barcham.
Ryan's 25-yard shot put Scunthorpe ahead and Karl Hawley's close-range strike made it 2-0 after the interval.
Substitute Freddie Sears fired the ball in from close range to make it 2-1.
But although Colchester pressed for an equaliser in the closing stages, Scunthorpe held on and were unable to prevent a club record ninth successive league defeat.
VIEW FROM THE DRESSING ROOM
Scunthorpe United boss Brian Laws told BBC Radio Humberside:
"It was always going to be a tough game, but we're delighted because it was that game we wanted to win to get out of the bottom four.
"But it's only a small step, that's all it is. Let's not get carried away and I've told the players that, but we're undefeated in 2013 which is good.
"It was hard work and we had to work harder than them. I thought at times that we played really, really well and we looked in good control.
"It's a battle - we're in a dogfight. There's going to be times when it's good and there's going to be times when it's ugly, and we have to defend as a team when it's ugly."