Swansea City's unbeaten run came to an end at Glanford Park as a second-half penalty from Joe Garner earned Scunthorpe all three points.
In a game that Swansea dominated on a horrendous surface, Alan Tate
's dubious foul on Garner after 71 minutes inside the area ended their four-game winning streak.
The game kicked off on time with another healthy Swans following having made the long trip from south west Wales and beyond.
It was obvious early on that the Swans were going to be in for a battle with the small Glanford Park pitch displaying more signs of sand than grass.
The Swans were looking to use the flanks as much as possible as Nathan Dyer and Scott Sinclair had early touches, with Neil Taylor also pushing forward from left-back.
Craig Beattie was also showing plenty of aggression up front as the Swans were determined to try and play their normal passing game despite the terrible surface.
Swansea's first chance came in the 11th minute when Mark Gower and Beattie set up Sinclair. The winger cut in from the left and fired a fierce shot on goal which Josh Lillis did well to save.
Dyer was the next to try his luck four minutes later after working space for himself on the edge of the area, but his shot flew well over the top as the visitors remained on top.
Scunthorpe gave the Swans a fright in the 16th minute as a reverse pass from Joe Garner picked out Andy Hughes free inside the area, but the striker fired straight at Dorus de Vries.
A minute later and Andrew Wright became the first player in the referee's notebook when the Scunthorpe right-back fouled Sinclair on the touchline.
Swansea picked their passes well to free Angel Rangel down the right and the Spanish full back drilled a shot just wide of the far post.
The visitors should have taken the lead in the 25th minute with a superb build up between Dyer and Joe Allen down the right. Beattie got involved to play Allen through on goal, but the midfielder saw his shot cleared off the line by Andrew Wright.
Gower came close with two efforts straight after, while de Vries did well to deny Joe Garner at the other end after the striker got away from skipper Alan Tate
with 31 minutes gone.
Scunthorpe found themselves with two more yellow cards in quick succession when Michael Collins and Andy Hughes were booked for fouls on Allen and Taylor respectively.
Beattie had the next chance in the 39th minute when he beat the offside trap to race onto a Dyer pass, but he fired over.
Dyer tried his luck himself three minutes before the interval as Lillis was forced to parry away his shot.
Half-time: Scunthorpe 0 Swans 0
Swansea had to endure early pressure in the second-half as the home team played towards one of the few terrace areas in the league behind de Vries' goal.
But Swansea came back in a lively opening.
The first real chance of the half came on the hour when Gower drove to the by-line before firing in a low cross which Lillis did well to parry away from the challenging Beattie. As the ball bounced around the area, Ashley Williams fired over.
Two minutes later Dyer won a free kick for a foul by Ben Gordon. Gower delivered it from the edge of the area and Lillis was forced to tip Williams' header over the bar as Beattie challenged.
Allen had a shout for a penalty turned down straight after as the Swans were back on top.
Swans boss Brendan Rodgers stepped up the pressure by bringing on Stephen Dobbie for Britton in the 66th minute as the visitors had another shout for a penalty turned down for handball.
A relieved Scunthorpe went straight down the other end and Garner sent Ben Gordon in on goal only for de Vries to pull off a good save.
But the Swans went behind in the 71st minute against the run of play when Alan Tate
was adjudged to have brought down Joe Garner. And despite the protests, Garner picked himself up to blast the penalty beyond de Vries.
Swansea had another penalty shout for handball turned down as they piled on the pressure with Scunthorpe defending in numbers.
But in the end time ran out for the Swans.