Andy Welsh has admitted Sunderland under-23s must improve ahead of the Premier League 2 campaign.
The young Black Cats were defeated in disappointing fashion at Leeds United on Saturday as they lost 3-1.
Mallik Wilks scored a first-half brace before Dan Wright halved the deficit with a close-range finish in the second 45.
However, any hopes of a comeback diminished when Alex Purver restored Leeds’ two-goal cushion late on with a well-placed header.
And speaking post-match, Welsh called for a reaction from his players and stated they must improve quickly.
“We struggled defensively and it was very difficult,” he said. “We have done a lot of work defensively so some of the lads have got to take a look at themselves and take on board all the things we are telling them.
“There are two distinct things with this group because last season we were very good off the ball and excellent on the ball.
“This year we are good on the ball but without the ball we are too nice to play against and that goes throughout the team," he continued. "We could’ve scored five or six against Leeds, easily.
“But we need to have more devilment about us defensively and in one-on-one duels we must be stronger.”
