PHIL PARKINSON admits Sunderland’s fringe players failed to fire as his much-changed line-up crashed to a Leasing.com Trophy defeat at the hands of Leicester City Under-21s.

Parkinson made eight changes to his starting line-up for his EFL Trophy debut as Sunderland boss, handing the likes of Grant Leadbitter, Dylan McGeouch, Benji Kimpioka and Marc McNulty an opportunity to push their claims for a more regular role.

However, despite taking the lead through Chris Maguire’s free-kick, Sunderland’s experienced side were unable to press home their advantage, with Leicester’s youngsters turning the game on its head thanks to two goals in three second-half minutes from George Hirst and Kiernan Dewsbury-Hall.

Sunderland will still progress to the knockout stages of the competition if they win at Scunthorpe United next Tuesday, but Parkinson has learned some valuable lessons from last night’s defeat.

With the reopening of the transfer window now less than two months away, the deficiencies within the Black Cats’ current squad are becoming increasingly clear.

“The main thing with this Tuesday, Saturday, Tuesday period of cup games is to look at everybody so we can build up a picture for January,” said Parkinson. “That is the key for us really.

“It’s been a disappointing night. We got off to a great start, but it’s a big learning curve for myself. We’ve changed the team around and pieced the team together to give players an opportunity, but two things stood out.

“The team were too open out of possession, exactly how we don’t want to be, we looked vulnerable in terms of the counter-attack, and then secondly, we played backwards too many times.

“Since I’ve been here, we’ve spoken about penetrating the opposition and getting shots and crosses in, but we played backwards too often. Possession is good, but it’s got to be possession with a purpose, and I felt we went away from what we’ve been doing.

“It was vastly different personnel in the team, lads we haven’t done a great deal of team play with, but when you’re on the touchline and it’s almost like a 4-2-4 out of possession, it’s a hell of a big pitch to try to cover and you can get exposed. Even against a young team, that’s not the way to play here.”

None of Sunderland’s returning players impressed, with Leadbitter and McGeouch struggling against midfield opponents with little or no senior experience, and Kimpioka failing to make the most of his first senior start for the best part of a year.

Parkinson cited a lack of match fitness as a mitigating factor for some of his players’ failure to perform, and accepted much of the blame for his side’s below-par display.

“I picked a team that was very open and we got exposed at times,” he said. “Two or three are very low in terms of match fitness and that probably showed. We’ve got to kind of accept that.

“We played Alim (Ozturk) and he’s come off injured, (Laurens) de Bock, who was playing his first game for a few weeks after being injured, and McGeouch hasn’t played for a while as well.

“We just left ourselves exposed. That was the team I picked, and when you’re on the touchline thinking, ‘We look exposed against a young team’, it just shows you that in league football, you can’t leave yourselves open like that.”

Ozturk’s injury was a major blow, with the Turkish centre-half appearing to suffer a recurrence of the hamstring problem that had sidelined him for almost two months.

He pulled up in obvious discomfort on the edge of his own area, and was clearly frustrated as he hobbled from the field.

“I’m really disappointed for him,” said Parkinson. “He's had a full week's training and it’s disappointing. I don’t know the extent of it yet, I just know it’s his hamstring and I’ll find out later."