Sheffield United take away what could prove a huge three points in their charge for the second automatic promotion place, after a stuttering run lately.
Edouard Michut put Sunderland ahead after half an hour with his first goal for the club, before James McAtee equalised right before half-time.
Tommy Doyle's controversial free-kick goal gave the Blades the winner however and moves them six points clear of third-placed Middlesbrough.
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Sunderland 1-2 Sheffield United
Sheffield United have a corner and are in no rush to take it.
They try and play it short and keep it around the flag as Paul Heckingbottom urges them on from the touchline.