Brian Brobbey scored a hat trick in a losing cause as Manchester City maintained their 100% Premier League start with a frantic 5-3 win over Sunderland.

In a game characterized by poor defending, City struggled to slow down the fired-up visitors at the Etihad Stadium, with Brobbey a constant thorn in their side.

Ultimately two goals from Antoine Semenyo and a late strike from Erling Haaland finished the job for City, for whom Enzo Fernández and Rayan Cherki were also on target.

Unlike in last week's Manchester derby, City failed to assert control against a Sunderland side clearly not drained by its midweek Europa League excursions.

For new manager Enzo Maresca, however, it was a fifth successive league win and City head into the international break with a three-point lead at the top.

City were given an early warning as Sunderland broke from deep and Enzo Le Fée played in Nilson Angulo but he steered wide.

Sunderland paid for that miss as Fernandez fired home from a ninth-minute free kick after Iliman Ndiaye was brought down by Dayann Methalie.

Goalkeeper Robin Roefs left a huge gap at his near post having set up with only two men in the wall. Fernandez took full advantage, curling in his first goal since his £125 million move from Chelsea.

Sunderland responded quickly and were back level three minutes later as Lee played a superb ball between Rúben Dias and Matheus Nunes and Brobbey deftly flicked beyond Gianluigi Donnarumma.

Sunderland's good work up front contrasted with that at the back, as an attempt to play out plunged them into more trouble. Kevin Danso gifted possession and confusion reigned before Cherki tucked in.

Again City could not hang onto the lead as Le Fée played in Thomas Meunier and his square pass was turned in by Brobbey. The goal was awarded after a lengthy VAR check for offside, leaving Donnarumma to vent his anger at the standard of Cherki's defending.

City regained the lead before the break after a Cherki cross led to more panic in the Sunderland area. The Black Cats claimed Marc Guéhi handled but nothing was given and Semenyo lashed in.

Haaland should have had another but inexplicably missed an open goal after being teed up by Ndiaye and Brobbey was denied another when a shot took an awkward deflection and was palmed onto the bar by Donnarumma.

City's fourth came early in the second half as a Cherki pass intended for Haaland ricocheted off a defender and bobbled into the path of Semenyo. Again he finished clinically.

Yet still City were not convincing and more sloppy play allowed Sunderland back in.

Angulo brought down a long ball as he ran in at the back post and although his effort looked like it might cross the line, Brobbey took no chances and pounced to compete his treble.

Remarkably it could have been 4-4 moments later as Donnarumma failed to deal with a cross and the ball bounced off Dias toward goal. The Portuguese sprinted back to hook off the line.

Haaland finally put the result beyond doubt.

Making amends for his earlier miss, the Norwegian slid in at the back post to tap in after Josko Gvardiol broke clear down the left nine minutes from time.