The result did not confirm that the days ahead belong to Arsenal, but they have a stake in the future. If Chelsea's display was spasmodic and clumsy, it was, at least in part, because they had no answer to the rhythm of opponents who might now be ready to enter a new phase. After five years without a trophy there should be an ache to succeed.
Arsenal still did not look commanding in defense. That was to be of no account as, from the latter stages of the first half, they hit a tempo that made Chelsea ache. While the losers wonder about the years ahead, Arsenal has reached a moment when they must no longer depict themselves as a work in progress.
It is time simply for the club to be a real power. The age profile will usually be in their favor, and while Theo Walcott has seemed to regress at times to the status of impact substitute, he was a force here. Arsene Wenger would be happy to see that as the embodiment of the Arsenal project.
This win did not cancel out three losses already endured at the Emirates to supposedly lesser visitors, but it encourages an assurance that will limit the number of lapses. Results transform attitudes, and Arsenal had waited a while for this alchemy.
They presented themselves with a 3-0 lead after opening the scoring on the verge of the interval. A first victory over Chelsea in 25 months loomed, since Carlo Ancelotti, the Chelsea manager, has a team in decline. Their response with a goal was a last spark of pride in a squad that looked burnt out.
Arsenal's play was smooth but lacking a contrasting pointedness in the penalty area.
There had nevertheless been a rising tempo and confidence, which was rewarded in the 44th minute. Alex Song began the move. His pass brushed against Cesc Fabregas before Jack Wilshere returned play to Song, who shot low past Petr Cech from an angle on the left.
Arsenal increased the tempo in a fashion that suggested memories of meetings with Chelsea had been cleansed from the memory. Arsenal's last victory over Chelsea had been in Nov. 2008.
Arsenal, a goal ahead, had the composure of a side that could afford to be calm, particularly since there was, by then, an erratic tone to Chelsea. With 51 minutes gone, Michael Essien's effort to tackle Robin van Persie merely guided the ball to Walcott, and he drew Cech before setting up Fabregas to shoot into the unattended net.
The competence deteriorated further at the next Arsenal goal, two minutes later. Walcott dispossessed Florent Malouda, and when Fabregas returned the ball to him the finish was elementary. By that stage, all that remained of the once formidable Chelsea was the persistence that counted at a Didier Drogba free kick, with Branislav Ivanovic leaping above Laurent Koscielny to head a goal in the 57th minute.
In its own way, even that moment has its uses for Arsenal as an indication that they can be more efficient in defense.