Kim Hellberg praised a "brilliant" performance from Alex Bangura, insisting the defender showed players can force their way into his plans with effort on the training ground.
Bangura, 26, has not played for Boro for 18 months, with his last appearance coming at the end of the 2023-24 season.
But after impressing the new manager in two sessions at training this week he was rewarded with a start and 90 minutes as Middlesbrough came from behind to beat Derby County.
"I heard he hadn't played in a long while but he showed me that he has so much skills and a good attitude in training," said Hellberg.