Nowhere was that optimism and anticipation greater than Brentford, an enclave of west London deprived of top-flight football for 74 years and desperate to fill their new stadium for the first time en masse. To heighten the excitement still further, crowds were able to return without restrictions on capacity for the first time, meaning 16,479 supporters crammed into this compact but comfortable arena surrounded on three sides by railway lines.
And how Thomas Frank's team rose to the occasion. Sergi Canos fired a 22nd-minute shot past Bernd Leno to settle any lingering nerves before the hosts doubled their advantage 17 minutes from time with a goal from a throw-in that typified how they out-fought and out-thought opponents who really should know better in an emotional 2-0 win.
"We're just a bus stop in Hounslow, but we're top of the League," said Frank afterward, summing up the David and Goliath feel.
Yet the most damning aspect of this is that it wasn't much of an upset. Sources at Brentford were quietly confident all week they could deny their underdog status and cause a stir, conscious of the soft underbelly Arsenal have long carried.
What does it say about the Gunners that they were proved so emphatically correct? The opening game of a campaign is palpably too early to declare a club in crisis, but then this result doesn't reflect 90 minutes but an unfinished summer.
If it is misfortune that both Pierre-Emerick Aubameyang and Alexandre Lacazette missed the game through illness, and key midfielder Thomas Partey was absent due to an ankle injury, there are still questions to ask about a process that left a 20-year-old, Folarin Balogun, to lead the line on his debut in such circumstances.
Balogun could be anything, but he isn't ready yet. And neither were Arsenal, despite this being such a vital game given the fragile mood around the club, the culture shift Mikel Arteta is trying to implement and a fixture list that pits them against Champions League winners Chelsea and Premier League winners Manchester City before the end of the month.
White and defensive partner Pablo Mari struggled all night. Their third summer signing, Nuno Tavares, made an ineffective late appearance as a substitute as Arsenal failed to show any sustained attacking cohesion to force their way back into the game. They ended with 22 shots but just four on target, a small indication of the desperation on show.
Bukayo Saka, applauded on by all four corners of the ground in a show of support after missing the decisive penalty in England's Euro 2020 final defeat to Italy, brought some fresh impetus as a second-half substitute to supplement the flashes of purpose from Emile Smith Rowe and Kieran Tierney. That trio continues to resemble Arsenal's best hope of progress.
Meanwhile, Willian, earning £100,000 a week, was nowhere to be seen and wantaway midfielder Lucas Torreira used the half-time break to post a picture on social media of himself alongside his family at a theme park in Madrid. It is a little early for Arsenal to be on the roller coaster, but here they are.
Calum Chambers, perhaps an unusual choice at right-back with Hector Bellerin still at the club and on the bench alongside Cedric Soares, was beaten too easily by Canos, as was Leno at his near post. Leno, remember, is the only senior goalkeeper at the club after the Gunners sent Emiliano Martinez to Aston Villa last summer and Mat Ryan ended his loan spell by returning to Brighton & Hove Albion.
At the very least, Leno needs more competition on this evidence, especially after being crowded out to concede the simplest of goals that killed the contest. A long throw-in from substitute Mads Sorensen reached the near post where Ivan Toney pressurised Leno and Chambers to force the ball on and Christian Norgaard nodded in his first goal in English football.
Arteta cut a frustrated figure throughout but insisted they would not panic in the market, despite the club ideally looking for a creative midfielder, a backup goalkeeper and a striker with less than three weeks of the summer transfer window left.
"My focus is with the players that we have, try to make them play the best as possible, get the best out of the team and find the way to win football matches," he said. "We are very clear on what we wanted to do, what our strengths are and what we can improve, and I don't think today's performance shows anything different from what we already think."
Not showing anything different is precisely the problem. And the clock is already ticking.