Elliott Dickman has urged his Sunderland youngsters to develop a nastier side after their defeat to Newcastle United U23s.
Early strikes from Lee Connelly and Jack Diamond had handed Dickman's side an early advantage, but they suffered a dramatic collapse as the Magpies ran out 3-2 victors.
And while the Sunderland U23 boss feels his side have improved over the course of the season, he is keen to see his players develop a more 'nasty' side as they look to secure more positive results.
He feels that will to win is required should the Black Cats' youth crop wish to progress into senior football.
"The team has definitely improved, but there's one thing we definitely struggle in," he admitted.
"We have too many very nice players, and we need one or two more nasty players.
"If you speak to the lads they'll tell you they want to win and that it means everything to them to win, but there's a difference between saying that and actually doing that.
"I think there's too many who need to start to man up and stop being too nice.
"They are young, but they're not in the under-18 side any more.
"They're in a different environment where you're potentially a step closer to the first team."
The Black Cats were dealt a blow in the first half when centre back Jack Bainbridge limped off with a hamstring injury.
The ex-Everton man is one of the more senior members of Dickman's squad, and the Sunderland chief was disappointed to the defender.
"He's done fantastic and has been one of our best players all season," said Dickman.
"I'm really pleased with how he has progressed.
"He came in the summer and has added a bit of maturity to the dressing room and it was a big blow.
"He brings a calmness to the side and he helps to organise things at the back.
"But that's football, you get injuries and it's chance for Alex [Storey] to come in."