Riley McGree's first half goal put Middlesbrough in frontRiley McGree's goal gave Middlesbrough a deserved 1-0 win over Sunderland in the first Tees-Wear derby since 2018.
McGree brilliantly controlled Ryan Giles' left-footed cross, but scored fortuitously after Luke O'Nien's last-gasp tackle deflected on to his foot.
Sunderland offered little in manager Tony Mowbray's second game in charge, while the hosts missed several chances to extend their lead.
It gave Boro their second Championship win this season, lifting them to 14th.
More than 30,000 filled the Riverside Stadium to watch Chris Wilder's team after a poor start to the season, which saw them win just one of their opening seven matches.
Alex Pritchard should have opened the scoring after seven minutes for Mowbray's Sunderland but after that, Middlesbrough's performance belied their early-season place in the Championship relegation zone.
Australian McGree could have had a first half hat-trick, with a volley bouncing over the bar and a right-footed strike well saved by Black Cats keeper Anthony Paterson after a free-flowing attacking move.
He scored with the second of his three chances, giving Boro a 1-0 lead at the end of a first-half which threatened to boil over at times.
Wilder's team continued to have the upper hand in the second half, with Matt Crooks and Rodrigo Muniz going close to doubling their lead.
Despite some late Sunderland pressure, the hosts hung on to jump eight places and extend a league unbeaten run against Sunderland. which has lasted 14 years.
It meant Mowbray, who grew up in Middlesbrough and captained and managed the club, suffered his first defeat as Black Cats manager.
