Trossard has been a revelation since joining in January, comfortably justifying the £26million paid to buy him from Brighton.
The 28-year-old Belgian scored the only goal yesterday, as Arsenal beat Everton to maintain their unbeaten start to the season. It was his third goal since joining the Gunners, and in that time he has also weighed in with 10 assists.
Trossard has quickly established himself as a valuable member of Arteta's squad, which makes it remarkable to think his move to Emirates Stadium so nearly did not happen.
Arsenal went into the January transfer window trying to sign Ukrainian winger Mykhailo Mudryk, but Chelsea trumped them with a huge deal that could eventually be worth £89m. The Gunners pivoted to quickly wrap up a move for Trossard, who arrived five days after Mudryk joined Chelsea. The pair's fortunes since then could not have been more different.
Trossard left Goodison Park yesterday with Arsenal fans chanting his name and the man-of-the-match award tucked under his arm. Mudryk, in contrast, was hooked after just over an hour, as Chelsea were held to a 0-0 draw at Bournemouth, and is yet to score in 21 appearances for his new club.
Trossard has hit the ground running, thanks undoubtedly to knowing the Premier League from his three-and-a-half years at Brighton — and he is unlucky to not be starting more games under Arteta. He came off the bench yesterday, replacing the injured Gabriel Martinelli after 24 minutes, and seamlessly slotted into the left side of Arsenal's attack.
His ability to play a number of positions makes him a valuable asset. Trossard has featured in midfield for the Gunners, while he led the line at times last season in the absence of Gabriel Jesus. Trossard is able to play so many positions because he is two-footed, so much so that at times he bears a resemblance to former Gunner Santi Cazorla.
Indeed, his goal yesterday was an excellent finish with his weaker left foot. Arsenal worked a short corner well, and Bukayo Saka picked out Trossard with a cut-back. He ran onto the ball, guiding it first-time past Everton goalkeeper Jordan Pickford via the post.
"I've been practising all my life on both feet and you can see that it helps you in the game as an attacker," said Trossard. "It's so helpful if you're good on both feet that you can go either way and score goals with both feet, so it's nice."
"You know the competition in the team. We have so many good players, but I'm happy at the moment and happy I could contribute today with the goal."
It was always going to take a special goal to break the deadlock in a game Everton did well to turn into a scrappy affair.
Arsenal dominated possession and, though they lacked penetration, were able to rely on Trossard's brilliant late finish to save the day. He will have an important role to play over the coming months, with Arsenal now having to juggle competing in the Champions League and Premier League.
They kick off their European campaign on Wednesday, at home to PSV Eindhoven, and Trossard could well earn a start, given Martinelli was forced off yesterday with a muscle problem. In seasons gone by, such an injury would be a disaster for Arsenal, but there is a real sense now that Arteta is building a deep squad.
The fact he rotated his goalkeepers yesterday, with David Raya earning his debut and Aaron Ramsdale dropping to the bench, underlines that feeling of a real strength in depth.