The visitors arrived under new management after Ange Postecoglou replaced Nuno Espírito Santo during the international break, but his first game in charge could hardly have been more testing.

Forest had won only three of their previous eleven league matches, and they struggled to adapt to Postecoglou's possession-based philosophy against an Arsenal side who controlled proceedings from the start.

Chances were scarce in the opening half, but Arsenal found a breakthrough just before the interval. Martin Zubimendi, making his mark since his summer move, unleashed a superb volley from distance to score his first goal for the club, and the first of his senior career from outside the box.

The Gunners struck again almost immediately after the restart.

Viktor Gyokeres, signed in the summer to sharpen their attack, finished clinically from close range after meeting Eberechi Eze's inviting cross.

Forest nearly found a lifeline when Dan Ndoye's delivery deflected off Chris Wood and forced David Raya into tipping the ball onto the bar, but the hosts quickly reasserted their control. Gyokeres then rattled the post himself as Arsenal pressed for a third.

Mikel Arteta's men closed out the contest with ease as Forest's resistance faded. Substitute Ryan Yates and James McAtee could not shift the momentum for the visitors, who conceded again late on when Zubimendi rose highest to head home his second of the afternoon.

The win gave Arsenal three victories from their opening four matches, bouncing back strongly from their narrow defeat to Liverpool before the international break.

Arteta praised his side's composure, saying: "We played with maturity and intensity. The players reacted in the right way."

For Forest, the defeat marked a second successive 3-0 reverse, underlining the challenge Postecoglou faces in lifting a side low on confidence.

Arsenal are for now top of the Premier League table on nine points from four matches, while Nottingham Forest are mid-table with four points from their opening three games.

Arsenal turn on style to sink Nottingham Forest in comfortable Emirates win