The Iron lifted themselves off the foot of the table with the stunning result, ending a run of five straight defeats.
“This was a massive win for us,” said manager Alan Knill, who enjoyed his first win in charge.
“After last week’s 6-0 defeat at Norwich the first thing I wanted from my team was a performance.
“We are still in a difficult position and we’ve got a big match coming up against Reading (tomorrow) night where we need another big performance.”
QPR boss Neil Warnock shrugged off the loss with his side still nine points clear at the top.
His side travel to Barnsley tomorrow but Warnock is confident their won’t be any lasting effects from Saturday’s drubbing.
“It was one of those days that sometimes happens in football,” he said. It was a game that we could and should have won.
“We were much the better team for the first half. We got an early goal and if we had got a second I am sure it would have killed Scunthorpe off.
“We had the chances but we failed to take them.”
Warnock’s mood will have been helped by Norwich’s failure to close the gap as they lost 3-0 at Swansea, a result that leaves the Swans only one point off automatic qualification, level on points with third-placed Cardiff, who won 3-1 at Doncaster. Swans boss Brendan Rodgers said: “We have got the same number of points as last season. We have to be one group going into the final six games.
“We can only control our own situation. It’s a great achievement but we have to push on now.”
Swansea host Hull tomorrow night.
But it is more than just a three-way battle for second place, and Nottingham Forest boss Billy Davies is backing Reading to snatch it after they closed to within four points with a 4-3 win at the City Ground.
Simon Church was the Royals’ match-winner with a close-range finish in injury time after Lewis McGugan’s 88th-minute penalty looked like being enough to salvage a draw for Forest.
“You have certainly been looking at candidates to finish in the top two,” Davies said.
“They might have work to do but they have momentum on their side and have the qualities that could take them all the way.”
The defeat was a blow to Forest’s hopes of finishing in the top six, leaving them four points behind Leeds in the final play-off spot.
That is despite Leeds losing 3-2 to Millwall at the Den as the hosts scored two early goals through James Henry and Liam Trotter.
However, Leeds boss Simon Grayson is refusing to panic despite recent poor form.
“There will be many twists and turns,” he said.
“This defeat won’t decide whether we get a play-off place.”
Leicester have closed to within five points of Leeds, but Sven Goran Eriksson found reason to be frustrated even after a 4-0 thrashing of Burnley.
Eriksson said: “We were back to form, it makes me happy but also I am a little bit angry.
“It was a top-class performance from everyone, including the three subs. Everyone did fantastic.
“But we should be playing like this more often, and that makes me angry.”
Scunthorpe’s victory and a 1-1 draw for Preston at Portsmouth means Sheffield United have sunk to the bottom after losing 2-1 to Middlesbrough at Bramall Lane, where Marvin Emnes grabbed a late winner for the visitors. “It’s a cruel game. I feel as if we’ve been mugged,” Blades boss Micky Adams said.
Barnsley enjoyed a 4-2 win over Bristol City, while Hull kept alive their play-off push with a 2-1 away win over Watford. Ipswich put more pressure on 21st-placed Crystal Palace with a 2-1 win, while Derby edged away from danger as they drew 2-2 with Coventry.