Arsenal returned to the Premier League summit with a dominant 3-0 victory at Brentford, where Fabio Vieira scored on his first league start on Sunday.
Mikel Arteta's side saw their winning start ended by defeat at Manchester United in their previous league match, but they responded in emphatic fashion to move a point clear of Manchester City and Tottenham.
First-half goals from William Saliba and Gabriel Jesus put Arsenal in control, before Vieira – in for the injured Martin Odegaard – added a brilliant third after the interval.
With the points safe, Ethan Nwaneri, aged just 15 years and 181 days, became the youngest player in Premier League history as he appeared from the Arsenal bench for the closing stages.
Gabriel Martinelli slipped to spurn a glorious chance inside two minutes, but Arsenal soon punished Brentford for a timid start with two goals in quick succession.
Saliba met Bukayo Saka's corner with a near-post glance, which bounced off David Raya's right post and over the line before the goalkeeper could react, and then Jesus nodded in from Granit Xhaka's left-wing cross.
Saka and Kieran Tierney both fired off target from presentable opportunities, while Bryan Mbuemo flicked wide at the other end as Arsenal dominated the first half.
Vieira marked his full debut by whipping past Raya and in off the post from outside the area four minutes after the break.
Ivan Toney volleyed just over from an inventive free-kick routine, before Raya expertly denied a fizzing Jesus drive and a curling Saka effort as Brentford rarely threatened an unlikely comeback.
What does it mean? Arsenal banish Brentford demons
Arsenal were off the pace in their Premier League opener last season, losing 2-0 to newly promoted Brentford, but they banished those demons on Sunday.
The Bees had lost just one of their previous 17 top-flight London derbies at home yet proved no match for an in-form Arsenal, who picked up their sixth win in seven league games.
While Tottenham and Liverpool may prove tougher tasks in their next two league matches, Arsenal laid down another marker despite injury problems for the absent Odegaard and Oleksandr Zinchenko.
Saka continued his fine form for Arsenal as he laid on two assists to move to 37 goal involvements in the Premier League for the Gunners (18 goals, 19 assists).
That moved him clear of Nicolas Anelka (35) for the most Arsenal goal contributions in the competition while aged 21 or under, with Cesc Fabregas (63) the only player to tally more.
Toney was handed a maiden England call-up this week after scoring five and assisting two more in just six league games – only Erling Haaland (12) had managed more goal involvements in the Premier League ahead of this match.
But the Brentford striker failed to leave his mark in this seventh match, not registering a single shot on target and completing only eight passes in a quiet showing against Saliba and Gabriel.
Key Opta Facts
– This was Brentford's heaviest home defeat in the top flight since May 1947, when they lost to Blackburn Rovers by the same 3-0 scoreline.
– Arsenal have won more Premier League games than any other team so far this season (six). For the Gunners, it is just the third time they have won as many as six of their first seven games of a Premier League campaign – previously doing so in 2004-05 and 2007-08 under Arsene Wenger (both six).
– Brentford have suffered consecutive league defeats against Arsenal for the first time ever (2-1 in February and 3-0 here) – indeed, this is as many defeats as they had in their first 11 league meetings with the Gunners combined (W6 D3 L2).
– Arsenal have won each of their last three London derby games in the Premier League, all of which have come during their first seven games this term (v Crystal Palace, Fulham and Brentford). This is the first time they have won three such games in a row since February-March 2015, with wins over Crystal Palace, QPR and West Ham.
Arsenal have the upcoming international break to prepare for the visit of Tottenham on October 1, when Brentford visit Bournemouth.