Sunderland boss Tony Mowbray said 17-year-old Jobe Bellingham is "a joy to work with" after the midfielder scored his first senior goals in their comeback Championship win over Rotherham.
The summer arrival from Birmingham, younger brother of Real Madrid and England midfielder Jude, scored either side of half-time in front of more than 40,000 fans at the Stadium of Light.
Hakeem Odoffin had driven Rotherham ahead with their first attempt after 20 minutes.
Bellingham headed an almost instant equaliser and then stroked home the winner early in the second half before spurning a couple of chances at completing a hat-trick.