Gabriel Martinelli rescued Arsenal as the Brazilian's last-gasp equaliser salvaged a 1-1 draw against Manchester City on Sunday when Pep Guardiola's defensive tactics backfired at the Emirates Stadium.

With City clinging to the lead given to them by Erling Haaland early in the first half, Guardiola made a series of unusually cautious substitutions that left his side without a recognised striker on the pitch in the closing stages.

But Guardiola's willingness to sacrifice his purist principles for a more pragmatic approach came back to haunt him.

It was a change made by Arsenal manager Mikel Arteta that proved decisive as Martinelli came off the bench to spare his team from a second defeat to a title rival after their loss at champions Liverpool in August.

"We don't try to be like this but when the opponent is better we defend deeper and counter-attack," Guardiola said.

"I would prefer not to do it but you have to at this level. I take a point and in some games we have to adjust. I think the result is fair.

"We played against a powerful team. We were incredibly tired. We had a lot of fatigue with many players. We also have a lot of injuries."

Arsenal moved up to second place, five points behind Liverpool, while City are languishing in ninth with just two wins from their first five league matches.

"I'm so proud of my players, the way we dominated almost every aspect of the game. Very disappointed not to win," Arteta said.

"I think we played better than last year when we beat them. Much better."

Already eight points adrift of Liverpool, it will take a significant improvement from Guardiola's men to catch Arne Slot's pace-setters, who have won their first five league matches.

Liverpool were the real winners from the slugfest in north London, which left Guardiola without a league win in five successive matches against an opponent for the first time in his reign.

On catching Liverpool, Arteta added: "We cannot control that. They win every match. It's going to be very difficult but if we play at this level we will be fine."

Despite grumbling about City having to play their Champions League opener against Napoli 48 hours after Arsenal were in action at Athletic Bilbao, Guardiola named an unchanged side. (AFP)