Preston remain right in the thick of a battle for a play-off place in the Championship after recording a 2-0 win that has pushed Sunderland closer to the drop.
Former Cork City striker Sean Maguire put Alex Neil's on track with his seventh goal in as many matches five minutes after the break.
— Trevor Carey (@trevorcarey1982) March 17, 2018
And then, after Sunderland defender Jake Clarke-Salter was red carded for the second time in a red and white shirt, Callum Robinson headed in the visitors' second in the 63rd minute.
After that Sunderland, whose fans jeered and booed after witnessing another positive start come to nothing, could not find a way back in the freezing temperatures and the fall into League One looks on the cards.
While Millwall's victory at Barnsley in the earlier kick-off created an opportunity for Sunderland to close a five-point gap to safety, it also saw the Lions leapfrog Preston in the battle for a play-off spot.
This season certainly has not gone to plan since Simon Grayson opted to swap these two clubs around last summer, only to lose his job on Wearside by November. Since then Sunderland have been unable to climb clear of trouble under Chris Coleman.
With time running out for both teams for contrasting reasons it was a fixture carrying plenty significance and Sunderland started the brighter, with teenagers Joel Asoro and Josh Maja lively in attack.
Clear-cut chances were few and far between for both sides. The best two of the opening half arrived in quick succession and one at either end of the pitch.
Sunderland's was first. Ovie Ejaria, on loan from Liverpool and impressive, played a lovely ball in behind the defence and there was just enough weight on it for Asoro to control.
The Swedish forward's touch took him away from goal and his second was an effort which was turned behind for a corner by goalkeeper Chris Maxwell.
Preston's counter attack from that flag-kick ended with a similar chance. Tom Barkhuizen, who caused problems down the right, was played in by Robinson's pass but goalkeeper Lee Camp was alert to stop.
The only other real chances of note before the break saw Bryan Oviedo's low effort after a well worked move held by Maxwell, while Ben Davies and Paul Huntington headed over from set-pieces for Preston.
But Preston soon took control after the restart when Sunderland's defensive weaknesses were exposed once again.
After Lee Cattermole had conceded a free-kick deep in his own half, Paul Gallagher delivered a cross to the back post where Maguire arrived unmarked to head in at the back post.
And things were to get worse. No sooner had Clarke-Salter, cautioned in the first half, been sent off for the second time for pulling back Alan Browne on the hour, Preston went further ahead.
Barkhuizen's delivery to the back post again was ideal for Robinson to head in, although once again he was left in acres of space to beat Camp.
The Sunderland fans started to depart early, those that stayed greeted the final whistle with boos.