Elliott Dickman says Duncan Watmore has been a "dream" to work with as the striker continues to build his fitness.
Watmore is closing in on a first team return after nine months out with a serious knee injury and completed 70 minutes in the Under-23 defeat to West Ham United.
The 23-year-old, who has also played 45 minutes against Manchester City’s second string, impressed with his workrate, pace, energy and movement in the defeat.
Under-23 coach Dickman praised Watmore, likely to return to the first team squad after the international break, for his impact and influence.
Dickman said: "I thought he was smashing. He likes to make those runs forward and the quality of the service to him second half was much improved on the first.
"Everybody has been saying it and it is important, you don’t want to rush him back too quickly.
"We are being sensible with him. He had 45 minutes last week, 70 this week and now it is up to the senior staff to decide what happens with him from here.
"From our point of view, with the Under-23s, he is great with the lads in the changing room.
"He is an experienced player, has been around the first team at Sunderland for a while and been involved in England set-ups. His experience is great for the younger lads.
"He is very intelligent and knows the game and has been a dream to work with.
"Now, he has some more minutes in his legs and it is up to the manager, the coaches and medical team to decide what the next step is for him.
"He was great for us," added Dickman.