The champions overtook the challengers as Manchester City defeated Arsenal 3-1 to usurp the Gunners and rise to the top of the Premier League table.
Defensive errors plagued Mikel Arteta's side against his former employers, who rendered Bukayo Saka's penalty inconsequential as goals from Kevin De Bruyne, Jack Grealish and Erling Braut Haaland handed the Gunners their first home league defeat of the season.
Contrasting injury news emerged from both camps an hour before kickoff, with Thomas Partey missing out for the hosts but Haaland being passed fit to start for the visitors.
A finish befitting that of the ever-prolific Norwegian would break the deadlock with 24 minutes gone, although it was De Bruyne rather than Haaland who would be the fortunate recipient of an undercooked backpass from Takehiro Tomiyasu.
Under pressure from Grealish, Tomiyasu attempted to prod the ball back to Aaron Ramsdale, but his weak pass provided a gilt-edged chance for De Bruyne, whose sumptuous first-time curling effort rose above Ramsdale before nestling into the back of the net.
As ever, the Arsenal response to going a goal behind was a wholly positive one, as Tomiyasu attempted to make amends with a close-range volley after 28 minutes but only succeeded in sending his side-footed attempt over the crossbar.
The Citizens' early time-wasting would also grind a few gears in the home crowd, with Ederson picking up a yellow card in the 36th minute, while makeshift left-back Bernardo Silva was also cautioned after three nibbles at Saka.
As Arsenal pressure continued to mount, Nathan Ake had to make a heroic goal-line clearance from Eddie Nketiah's shot, but Anthony Taylor immediately pointed to the spot after the striker was clattered by Ederson.
Despite fierce City protests, the spot kick stood, and Saka coolly sent Ederson the wrong way to deservedly level matters in the 42nd minute.
However, the woodwork came to the Gunners' rescue in the sixth minute of first-half added time, as Rodri's header bounced off the shin of Ake onto the crossbar just before the break.
VAR was not Arsenal's best friend against Brentford, but it certainly came to their rescue at the start of the second half, as a tangle between Gabriel Magalhaes and Haaland ended with a penalty being given in the 56th minute.
To the elation of Arsenal fans, though, Haaland was just offside, and hearts were also in mouths when Ramsdale spilled the ball in a dangerous area before Jorginho - who stepped up admirably in Partey's place - cleared Manuel Akanji's effort off the line.
There was an abundance of threat when Arteta's men ventured forward too, but the sucker punch arrived in the 72nd minute, as a sweeping City move ended with Grealish's effort taking a slight nick off of a sliding Tomiyasu and beating Ramsdale.
Any faint hopes of an Arsenal comeback were virtually extinguished with 82 minutes gone, as another slick City sequence ended with De Bruyne teeing up Haaland to fire his 26th Premier League goal of the season into the far corner.
The Emirates stands soon began to empty, but those still present witnessed Nketiah send another header wide from Saka's cross in the 89th minute, and there was to be no miraculous comeback in the five minutes of added time that followed.
City have now leapfrogged Arsenal - who still have a game in hand - on goal difference ahead of a trip to Nottingham Forest on Saturday, while the Gunners visit Aston Villa in the lunchtime kickoff.
