Pep Guardiola needed a late Paddy McNair own goal to make a winning start at Manchester City as David Moyes lost his first game as Sunderland manager.
Sergio Aguero’s penalty, after Raheem Sterling was fouled by Patrick van Aanholt, gave City an early lead.
But Guardiola, who left England keeper Joe Hart out of his starting XI, saw his new side concede to Jermain Defoe.
City made few chances, but snatched an 87th-minute winner when debutant McNair headed into his own net.
It had been 195 days since City announced Guardiola would succeed Manuel Pellegrini at Etihad Stadium, and results stagnated during that period, with five wins from last season’s final 15 Premier League games leading to a fourth-placed finish.
Guardiola, 45, arrived in Manchester with six league championships to his name – three each from his spells at Barcelona and Bayern Munich – and brings an expectation he will guide City to a first Premier League title since 2014.
But any hopes of an instant revolution were curtailed by a lethargic performance that lacked creative spark, despite dominating possession against a side that only avoided relegation in their penultimate game last season.
And, while City may have required good fortune for the decisive goal – McNair heading in Jesus Navas’ cross at the back post, it provides a winning platform for Guardiola, who was lacking injured first-team players Vincent Kompany, Samir Nasri, Nicolas Otamendi and new signings Leroy Sane and Ilkay Gundogan.
Hart’s absence from the starting line-up is the most eye-catching decision of Guardiola’s early days at City, and will raise the question whether the 29-year-old’s 10-year stay at Etihad Stadium could be coming to an end.
The former Shrewsbury player has made 347 appearances for City, winning two Premier League titles, an FA Cup, two League Cups and 63 England caps, but Guardiola opted to start with Willy Caballero.
The Argentine made a notable stop from a point-blank Defoe effort, before the striker slid home a cool finish.
Midfielder Yaya Toure was left out of the squad altogether, but the influential Ivorian may have been saved for Tuesday’s first leg of the Champions League qualifier at Steaua Bucharest.
John Stones, a £47.5m summer signing from Everton, looked composed at the heart of City’s defence alongside Aleksandar Kolarov, and fellow debutant Nolito put in an enthusiastic performance on the wing.
Sunderland’s preparations for the new season were torn apart by manager Sam Allardyce’s decision to leave for the vacant England job, but his departure opened the door for Moyes’ return to the Premier League.
The Scot’s reputation was knocked by a difficult year as Manchester United boss, followed by an equally chastening 12 months at Real Sociedad.
But he could well be liberated by the shift in pressure from replacing the legendary Sir Alex Ferguson at Old Trafford to starting out at a club looking to improve on last season’s 17th-placed finish.
Three of Moyes’ four summer signings featured, Donald Love starting at right-back, and Adnan Januzaj and McNair coming off the bench, but the latter’s debut will be remembered for the own goal he scored just three minutes and 35 seconds after coming on.
Despite rarely seeing the ball, Sunderland restricted the hosts’ chances and will be buoyed by the quality of their goal – Defoe scoring in his 16th Premier League season by slotting home from a Jack Rodwell through-ball.