Erling Haaland opened the scoring against the run of play after nine minutes and had looked to have secured all three points until Martinelli's leveller in the third minute of injury time.

While Arsenal boss Mikel Arteta made two changes from the side that beat Atletico Bilbao in the Champions League in midweek, Guardiola named an unchanged team for the third time in a row for the first time in three years.

Arsenal dominated the opening exchanges, but it was City who took the lead with their first shot of the game through Haaland who started and finished the attack.

The Norwegian striker fired home past Gunners' stopper David Raya after picked up a loose ball inside his own half and feeding Tijjani Reijnders before racing onto the return pass inside the Arsenal box.

City may have had a second goal on 20 minutes, but Reijnders' shot from just outside the 18-yard area was calmly collected by Raya.

Arsenal's only real chance to get on the scoresheet early on came from successive corners that were easily dealt with by new Gunners' goalkeeper Gianluigi Donnarumma.

There were calls for a penalty from the home fans on 32 minutes when Gabriel went down in the box after a push from Haaland, but play was waved on.

Rodri was, meanwhile, leaning back when fired over, with 38 minutes on the clock, after being teed up by a marauding Jeremy Doku.

When Arsenal did work their way into the box, with a good spell of pressure, the ball ultimately dropped to Noni Madueke, but he only managed to win a corner after his shot was deflected over the goal.

There were some nervy moments for City at the end of the first half with Arsenal more of a threat in the final third. Jurrien Timber delivered a super ball into the box, on 42 minutes, but Gyokeres failed to read the play and was caught well behind the ball.

A flying Donnarumma then punched clear a good Madueke cross before Riccardo Calafiori fired over the loose ball.

Madueke was by far Arsenals' best player in the opening period, and he forced a strong save from Donnarumma after working to create space inside the area.

The half ended with City pegged back in their own box and Arsenal believing they could find a way back into this tie.

Arsenal made a double change at the start of the second period with new signing Eberechi Eze brought on for Mike Merino as a fit-again Bukayo Saka replaced Madueke - despite the winger's fine performance in the first 45 minutes.

City, meanwhile, introduced Matheus Nunes to replace Abdukodir Khusanov.

Unlike in the first half, it didn't take long for the Gunners to create their first chance, with Martin Zubimendi blasting just over after he pounced on a failed City clearance before Eze forced Donnarumma to stand strong when he smashed in a shot on 49 minutes.

Saka clearly added a new dimension to the Arsenal attack - and fired in on goal moments later but saw his shot well blocked.

It was all Arsenal in the opening minutes but City were not to be contained for long, and Haaland hit a shot at Raya following a lightning break forward, having been fed through on goal by Doku.

Arsenal came close to levelling on the hour mark when Trossard's volley at the back post from a deep corner was blocked on the line. The same player then looked to have played in a perfect square ball for Gyokeres to finish, but the pass took the smallest of touches off Gvardiol and Haaland was able to clear.

Nathan Ake came on for Phil Foden on 68 minutes as Guardiola altered his defence to a back five in an attempt to see out the game.

City were able to take the sting out of Arsenal's relentless attack but a tense atmosphere remained at the Emirates with the home side running out of time to make a breakthrough in an increasingly gritty encounter.

Ake had to be at full stretch to stop Gyokeres from making headway inside the City box, at the expense of a Declan Rice corner that was punched well clear by Donnarumma. Calafiori then headed over a Saka delivery on 75 minutes, moments before Haaland was withdrawn for midfielder Nico Gonzalez.

Timber was also substitutes, for the final ten minutes, as Arteta turned to Martinelli to hopefully find a way through the City defence, although the next chance fell to Doku, who played a neat give and go with Reijnders - but he could only fire his effort across the face of the Arsenal goal.

Not quite ready to give up the goat, Arteta threw on Ethan Nweneri for Trossard for the final few minutes, as Guardiola looked to waste as much time as possible with the introduction of John Stones for Nico O'Reilly as Doku made way for Savinho.

The Gunners saw most of the ball as the game edged to the 90-minute mark and were given fresh hope when the fourth official announced an extra seven minutes of additional time.

Donnarumma had been a wall at the back for City the entire game but there was nothing he could do to stop a Martinelli chip from finding the back of the net, with 93 minutes on the clock, after the substitute was expertly played in behind the City defence by Eze.

A massive disappointment for Guardiola and City after leading the game since the ninth minute, but a massive result for Arteta and Arsenal, who's fans demand the Premier League title this season.

As it stands, Liverpool lead the standings with 15 points from their five matches played. Arsenal are in second with 10 points and City are down in ninth place with seven points.

EPL wrap: Man Utd edge Chelsea in battle of ten men