Mikel Arteta’s Arsenal denied familiar foe Ange Postecoglou from putting any points on the board for his new club.
Martin Zubimendi’s brace and Viktor Gyokeres’ goal cemented the victory for the Gunners at the Emirates.
Even though Forest have only one win to their name from four league matches, Postecoglou was quick to sympathise with his players amid the disruption and managerial change following the international break.
He attributed the outcome to the major disruption the Forest players have had to face and credited them for their work-rate.
"To keep my disappointment in terms of the result in context, it's no secret it's been a very disruptive week for the players. I can't fault the players' endeavour and effort."
There are a plethora of incomings who have yet to feature for The Tricky Trees substantially and make a notable impact.
Postecoglou opted for an unchanged lineup apart from deploying Morato at full-back due to Ola Aina’s unfortunate injury on international duty with Nigeria.
The Australian expressed his intent to integrate the new signings in the coming games, despite handing debuts to two players from the bench.
"We’ve only really had yesterday together as a group, so even though we’ve got games, I don't think that's necessarily a bad thing. There's a lot of the new signings that haven't really got the opportunity yet."
Nicolo Savona was called upon earlier than expected when stalwart centre-back Murillo hobbled off the pitch nearing the end of the first half with what Postecoglou described as simply a knock.
French winger Dilane Bakwa was also handed his debut for Nottingham Forest, and his cameo alongside James McAtee and Arnaud Kalimuendo highlighted the quality from the bench.
Postecoglou’s appointment sparked debates over whether his brand of football stylistically can mould effectively into the group of players at Forest, or if more emphasis should be placed on leaning into their existing strengths.
It was always a tall order for Forest to approach the game any different to their familiar game plan under Nuno against opponents like Arsenal.
However, going forwards, the influx of new additions affords Postecoglou the opportunity to introduce his own principles, while many of the existing players seem more than capable of adapting.
"It's a good opportunity between now and the next international break to integrate the new players but also start bedding down some of our principles in terms of how we want to play."
Nottingham Forest next travel to Swansea on Wednesday in the Carabao Cup and Postecoglou has voiced his urgency over implementing changes and how he wants the new-look Forest to perform against the Championship outfit.
"It won’t be months or weeks, it’ll be Wednesday night. This isn’t a project. On Wednesday night, we’ll start to see some real principles be embedded."