Daryl Murphy returned to haunt Sunderland as his 86th-minute winner for Nottingham Forest condemned the Black Cats to their second home defeat in the space of four days.
Murphy has played for both Sunderland and Newcastle in the past, and he clearly retains a fondness for the north east given the slick way in which he settled things at the Stadium of Light.
Receiving the ball from Barrie McKay in the area, Murphy turned neatly before drilling a low strike into the corner to secure a 1-0 win for Forest.
The result means Sunderland are still waiting for their first home win of 2017, and are now just a point above the Sky Bet Championship relegation places.
Forest have risen into the top 10, with their defensive solidity providing the foundation for their second league away win of the campaign.
Having watched his side collapse against Sheffield United at the weekend, boss Simon Grayson made four changes to his starting line-up, recalling a fit-again Lee Cattermole and handing deadline-day signing Callum McManaman his first start.
Sunderland had been extremely lethargic against the Blades, and while there was precious little quality on display as they returned to action against Forest, at least there was some energy and effort in the home side's ranks.
First-half chances were few and far between, although Lewis Grabban came close to an early breakthrough as he swooped on a loose ball in the Forest half in the ninth minute. Advancing towards the area, the striker fired in a left-footed strike that sailed narrowly over the crossbar.
Sunderland were the better side in the early stages, and Matt Mills had to produce an excellent block to prevent McManaman claiming his first Black Cats goal following his free transfer from West Brom.
Jonny Williams teed up McManaman in the area, but Mills timed his intervention perfectly to get in the way of the midfielder's shot.
The Forest skipper was at it again shortly before the interval, throwing himself to the ground to block George Honeyman's effort after Grabban's air kick caused confusion from a McManaman cross.
It was fairly scrappy stuff, but at least Sunderland were mustering a handful of efforts. Forest's first-half threat was restricted to a Liam Bridcutt run that was halted by Bryan Oviedo and long-range efforts from Kieran Dowell and Andreas Bouchalakis that flew harmlessly over the crossbar.
Sunderland remained the more threatening side at the start of the second half, and Forest goalkeeper Jordan Smith had to make his first save of the night when he got down well to keep out McManaman's effort after the winger had spun away from his marker in the box.
Forest threatened when Ben Brereton found himself in space in the area, but instead of firing away a shot, the midfielder turned inside, enabling McManaman to nick the ball away from him.
Williams came close for Sunderland, but Murphy struck with four minutes left. Tyias Browning conceded possession to McKay, and the substitute teed up Murphy to fire into the corner.