Plymouth Argyle's play-off hopes suffered a setback with a second successive defeat, but the result boosts relegation-threatened Scunthorpe's hopes of avoiding the drop.
The home side came roaring out of the blocks and nearly snatched a first-minute lead when midfield man Jim Goodwin unleashed a 25-yard drive which forced a finger-tip save from keeper Luke McCormick.
Scunthorpe dominated the early stages in difficult gusty conditions, but it was the Pilgrims that almost snatched the lead on the half hour with their first threat of the match.
Striker Jamie Mackie, a bargain buy from Blue Square Premier side Exeter City, cut inside to rifle in a fierce shot which brought the best out of goalkeeper Joe Murphy.
From the corner that followed Mackie did find the far corner of the net with a looping header, only to see it ruled out for a foul on Murphy.
The Plymouth striker had another chance early in the second half to break the deadlock, but scuffed his shot when well placed.
It was Scunthorpe who snatched the only goal of the game in the 55th minute with a real slice of good fortune.
Winger Ian Morris got free into the box to get in a shot which deflected off the outstretched leg of centre-back Russell Anderson and looped into the net over goalkeeper McCormick.
There was further woe for McCormick in the 71st minute when he was sent off for handling the ball outside his box and with no substitute keeper on the bench, midfielder Lee Hodges had to take over in goal.
He saved well from a free-kick from Goodwin, while at the opposite end ten-man Plymouth nearly grabbed a late equaliser when sub Rory Fallon was just inches away from converting a cross at the far post.
But it was Scunthorpe who nearly made it 2-0 in stoppage time when sub Ben May crashed a shot against the foot of a post.