Deadline-day signing Clayton Donaldson fired Sheffield United to a 2-1 win at the Stadium of Light to pile the misery on Sunderland.
Donaldson struck in each half to guide the Blades to a third win in a row - even though the former Birmingham frontman's goals were the first scored by the Championship new-boys away from home this season.
Sunderland, who have won just one of their opening six league games and have lost three in a row, pulled one back in stoppage time through Jack Rodwell's header but they now sit just a point above the relegation zone on another afternoon they will want to forget.
Sunderland 1-2 Sheffield United
