Grimsby Town lost their opening Leasing.com Trophy group match as Scunthorpe United collected all three points at Blundell Park
A double from striker Kevin Van Veen came either side of Harry Cardwell's equaliser as the visitors, who ended the game with 10 men after James Perch was sent off in added time, claimed a narrow win.
But a Town side showing 10 changes from their last league game provided plenty of positives in an encouraging display against more experienced opposition.
Town boss Michael Jolley's starting XI had only Elliott Hewitt remaining from the team that won at Walsall in the league at the weekend.
Sam Russell started in goal, with Joe Starbuck, Liam Gibson, Mattie Pollock and Sebastian Ring forming the defence.
New loan signing Ethan Robson was handed his debut alongside Hewitt in midfield, with Max Wright and Charles Vernam on the wings as Ahkeem Rose and Harry Cardwell began in attack.
The Grimsby substitutes were James McKeown, Luke Hendrie, Brandon McPherson, Cameron Painter, Joey Hope, Luis Adlard and Evan Khouri.
Former Town boss Paul Hurst named an experienced Scunthorpe starting line-up as they looked for their first competitive victory of the season having gained just one league point so far.
The Mariners created the first chance of the game on five minutes after a corner from Robson on the left was not fully dealt with. The ball was sent back into the box but Cardwell headed it over the bar.
At the other end, a low cross from Ryan Colclough on the right was cleared by Gibson after Yann Songo'o had broken through the middle.
A foul by Rory McArdle on Rose gave Town a free kick midway inside the Scunthorpe half on 15 minutes but Robson's delivery into the box was headed behind for a corner, which came to nothing as Hewitt's cross went over the bar.
A low cross from Vernam on the left was cleared for a throw-in, before a deep cross from Robson was punched clear by visiting keeper Jake Eastwood.
Vernam's foul on Colclough gave the away side a free kick in a dangerous position on 22 minutes. Colclough's ball from it was headed clear before a follow-up cross from James Perch saw Songo'o head straight at Russell.
Pollock had to concede a corner four minutes later to stop the progress of George Miller but the ball from the flag was headed clear.
A foul by Pollock on Miller soon afterwards came after Town had lost possession in their own final third and gave the visitors another free kick in a central position. From it, they took the lead as VAN VEEN stepped up and found the net with a powerful shot which gave Russell no chance.
Pollock was shown the first yellow card of the game after another foul on 31 minutes, before Alex Gillead let fly from 25 yards with a shot that flew wide of the target.
Miller won a corner for Scunthorpe on the right soon afterwards and Colclough's ball from it was not fully dealt with by the Grimsby defence. The winger eventually sent it back into the box but Miller headed over the bar.
The visitors had been on top since the goal but Town managed to create an opening on 38 minutes, although the cross from the right was slightly behind Rose and he could only head wide.
Colclough won another corner on the away right three minutes later but Songo'o's volley from it was deflected with for a goal kick.
A better opportunity for the Mariners came after Vernam was sent clear through the middle but he could not get the ball fully under control and after Eastwood came off his line to challenge, it ricocheted back off the attacker for a goal kick.
At the other end, Van Veen headed wwide from close range after more good play by Colclough.
Two added minutes were played at the end of the half and a weak shot from Rose in the secon of them went through to Eastwood.
That proved to be the last chance for the Mariners to get back on level terms before the break as Van Veen's goal remained the difference between the two sides at the halfway point.
No changes were made before the restart and Colclough sliced an early cross out for a goal kick.
A Robson free kick frrom the right was headed clear by Songo'o but soon afterwards, Town had their equaliser. A low shot from Rose was spilled by Eastwood and after first hitting the bar, CARDWELL put the ball into the net from close range at the secondd attempt.
A deep cross from Ring on the left was collected by the keeper, then Miller won a corner at the other end but it was dealt with by the home defence.
Van Veen cut in from the left and hit a curling shot that was comfortable for Russell, then good build-up play by the Mariners led to an opportunity for Vernam, whose shot was stopped by Eastwood.
Rose drew a foul from Songo'o just before the hour mark but Robson's free kick from just inside the Scunthorpe hlf came to nothing.
A stoppage came when Van Veen stayed down after being caught by Rose but the Dutchman was passed fit to continue after receiving treatment.
Colclough missed the target from 20 yards after being presented with a good chance on 64 minutes, before Hendrie replaced Robson as Town made the first substitution of the game.
A Scunthorpe corner soon afterwards was turned behind for another one on the opposite right flank, with Wright heading clear this time.
Colclough was booked for a trip on Wright, before a double substitution for Sccunthorpe saw Abo Eisa replace Gillead and Regan Slater come on for John McAtee. Brandon McPherson came on for Rose in Town's second change at the same time.
Scunthorpe had their lead back with 15 minutes to go as a cross from Colclough on the right was missed by Pollock and VAN VEEN had the time to control the ball and beat Russell from close range for his second goal of the evening.
Jordan Clarke fired a volley well wide from 20 yards as the away side went in search of a third goal that would make the points safe.
Another Scunthorpe corner came on the left as Wright did well to stop substitute Eisa but the visitors could not turn it into a chance in front of goal.
Van Veen was replaced by George Hornshaw for Scunthorpe and Luis Adlard came on for Vernam in the black and white of the Mariners with three minutes to go.
Five minutes of added time was signalled and the away side ended the game with 10 men as Perch was sent off for a poor challenge on Wright.
Wright won a corner on the Town right but Gibson's delivery was put wide at the near post in what turned out to be the home side's last chance of grabbing an equaliser to send the game to penalties as Scunthorpe held on for the win.
The focus now shifts back to the league, with the Mariners next in action on Saturday when Crewe Alexandra are the visitors to Blundell Park.
Town: Russell, Starbuck, Pollock (capt), Gibson, Ring, Wright, Hewitt, Robson, Vernam, Cardwell, Rose.
Subs: McKeown, Hendrie, McPherson, Painter, Hope, Adlard, Khouri.
United: Eastwood, Clarke, Songo’o, Colclough, van Veen, Perch, Gilliead, McArdle, McGahey (capt), Miller, McAtee.
Subs: Collins, Slater, Eisa, Bedeau, O’Malley, Hornshaw, Dawson.
Attendance: 1302 (202)
Next Up: Crewe Alexandra (H)