Third Division Huddersfield rubbed salt into Sunderland's wounds as they dumped the Division One side out of the Carling Cup.
Anthony Carss and Jonathan Stead fired the visitors into a 2-0 lead with just 20 minutes gone.
Kevin Kyle pulled one back for Sunderland and added a second in injury-time but a controversial third from Andy Holdsworth and an 87th-minute Andy Booth strike sealed the victory.
Sunderland defender Ben Clark was sent-off for handball in the build-up to Holdsworth's goal to add to the Black Cats' misery.
Huddersfield made a fine start and there were only 69 seconds on the clock when Michael Ingham found himself picking the ball out of his net after wing-back Carss had curled a left-foot free-kick into the top corner.
They doubled their lead when Sunderland's defence allowed Stead to bring Booth's lay-off under control before bending a shot into the top corner.
This time, Sunderland hit back with a vengeance, Kyle powering a near-post header past goalkeeper Ian Gray from Oster's 25th-minute corner to spark his side into life.
But disaster struck for the home side on 55 minutes.
Worthington broke into the box and saw his shot saved, and Booth's header from the rebound was blocked with his hand by Clark.
Holdsworth slotted the ball home anyway and referee Mark Cooper awarded the goal before sending Clark off for handball.
The few hundred delighted Yorkshiremen among a crowd of 13,516 were able to start their celebrations with three minutes remaining when Williams gifted a fourth goal to Booth.
Kyle collected his second from close range at the death, but that proved to be little consolation.
Sunderland: Ingham, James, McCartney, Bjorklund, Clark, Butler, Whitley, Thornton, Oster, Kyle, Proctor. Subs: Poom, Stewart, Williams, Babb, Leadbitter.
Huddersfield: Gray, Schofield, Mirfin, Scott, Yates, Carss, Worthington, Fowler, Holdsworth, Booth, Stead. Subs: Booty, Senior, Brown, Mattis, Newby.
Referee: M Cooper (West Midlands).