Scunthorpe were beaten 2-1 at Portsmouth on Saturday.
Leon Clarke rifled his side ahead on six minutes but the hosts hit back just seven minutes later through a goal from defender Gabor Gyepes.
With Sam Slocombe hobbling off injured early in the first half, substitute goalkeeper James Severn was called into instant action, diving low down to his left to save a penalty from Brian Howard after Niall Canavan was adjudged to have brought down Wes Thomas in the penalty area.
Both sides had chances but as the game drifted towards a dramatic finish, which saw Thomas bundle home from close range after a deep right-wing cross found him.
The Iron went into the game naming an unchanged side from the one that defeated Colchester United a week earlier.
Sam Slocombe started in goal, with Christian Ribeiro, David Mirfin, Niall Canavan and Tom Newey forming the defence.
The midfield consisted of Mark Duffy, David Prutton, Josh Walker and Jimmy Ryan, while Clarke and Karl Hawley led the attack.
The substitutes were James Severn, Paul Reid, Mike Grella, Andy Barcham, Connor Jennings, Robbie Gibbons and Chris Sedgwick.
Scunthorpe started the brighter team, on the front foot from the start and forcing Portsmouth into mistakes.
And they were to go ahead on six minutes as Newey's throw-in reached Hawley who linked up with Ryan before the ball reached Clarke, who thumped home from close range to make it five goals in five games since signing.
Two minutes later they had a shout for a penalty denied as Duffy played in Hawley in the area, who tumbled under a challenge. However, the referee was having none of it and waved play on.
Nevertheless, parity was restored on 14 minutes when a
Trying to build on that leveller, the hosts' next chance arrived in the 19th minute when a left-wing ball reached Darel Russell, who lobbed a volleyed effort over Slocombe, but also over the crossbar.
after a left-wing corner found Lubomir Michalik whose header was blocked by Slocombe, but Gyepes slams home the rebound in emphatic style.
Two minutes later, Scunthorpe's front two of Clarke and Hawley linked up brilliantly as the former flicked on Ribeiro's crossfield ball into the path of the latter, whose powerful drive was stopped by Mikkel Andersen.
Scunthorpe were forced into an early save on 23 minutes as Severn replaced Slocombe, who received treatment after the Portsmouth equaliser, and hobbled off.
Moments later, Ribeiro's delivery from the right caused a problem and Michalik sliced his clearance just wide of his own goal.
The hosts could have gone ahead in the 28th minute, however, as Adam Webster's pass found Izale McLeod, whose curler hit the crossbar.
They were awarded a penalty just two minutes later however, as Wes Thomas was tripped by Niall Canavan in the penalty area. There were Iron shouts it was outside the box but referee Andy D'Urso pointed to the spot.
Nevertheless, Severn guessed the way Brian Howard was sending his penalty, diving down low to his right and tipping away the shot.
Scunthorpe attached straight after and, after Ribeiro's cross, was only part cleared, Prutton's volleyed effort bobbled wide of goal.
Then, a free-kick from Prutton found Newey in the area but his header cleared the crossbar.
United's attacking continued and Clarke was next to come close, latching on to a pass from the right and advancing on goal before striking his effort into the side-netting.
The threat from the away side continued as the half wore on, with Duffy's clipped right wing ball drifting just wide of goal and narrowly evading the head of Clarke.
Then, on the stroke of half-time, the galloping Ribeiro found himself in striker territory after the ball bobbled into his path, but Andersen was quick to come out.
There was a final chance seconds before the interval as Hawley's backheel following Canavan's flick-on from a Prutton corner was saved by the home shotstopper.
The first opportunity of the second period arrived the way of Gyepes, whose shot after a Howard corner cleared the crossbar.
Scunthorpe came close again just a minute later though as Hawley tested Andersen again, with a low left-footed drive from a tight angle down the left of the area.
In the 51st minute, United hit the woodwork as Ribeiro's right-wing cross, after being played down the line by Duffy, just clipped the crossbar and Pompey cleared away the danger.
Then, two minutes later, Scunthorpe were close again, as Clarke curled a strike just wide of goal from the edge of the area after being teed up by Hawley.
In the 63rd minute, the hosts were inches away from going ahead as Thomas volleyed wide from close range after a right-wing cross.
Four minutes later, Ryan won back possession from Adam Webster and burst down the right flank before drilling across goal, and wide.
It was end-to-end stuff, and substitute Ashley Harris almost made an instant impact for the hosts, with a low effort which took a deflection and went wide. Nothing came of the subsequent corner as Scunthorpe cleared their lines.
With twenty minutes left on the clock, Ryan won the ball again and clipped in a cross for Clarke, whose header cleared the crossbar.
Then, the hosts came close just sixty seconds later, substitute Johnny Ertl came close, seeing his low drive blocked away by Severn after he had been teed up by McLeod.
With around 15 minutes left, United made their second change of the game as Sedgwick replaced Duffy.
The game descended into a lull in the closing stages as the match became scrappy and both sides lost possession too easily. As a consequence, chances were few and far between as the game neared its climax.
Portsmouth attacked in the 89th minute and Severn had to be alert to tip out a Mustapha Dumbuya effort low down to his right.
From a right-wing cross moments later though, the hosts went ahead, as Thomas bundled home at the back post from close range.
There were five minutes of stoppage time and Scunthorpe made a late change as Grella replaced Ribeiro, but they couldn't find that elusive leveller.
Indeed, Pompey could have got the last goal, as McLeod raced through on goal. However, his effort cannoned back into play off the post.
United had a last-gasp Clarke header saved from a Prutton free-kick as they went back to North Lincolnshire point-less from Fratton Park.
Scunthorpe are next in action on Tuesday night when they host Tranmere Rovers.
Portsmouth: Andersen, Dumbuya, Harley (Harris, 59), Williamson, Howard, McLeod, Gyepes, Russell (Ertl, 68), Michalik, Webster, Thomas (Obita, 90).
Substitutes not used: Walker, Compton, Eastwood.
Scunthorpe United: Slocombe (Severn, 23), Ribeiro (Grella, 90), Mirfin, Canavan, Newey, Duffy (Sedgwick, 76), Walker, Prutton, Ryan, Hawley, Clarke.
Substitutes not used: Reid, Barcham, Jennings, Gibbons.