The North Londoners headed into the game on the back of a 10-game unbeaten run in the Premier League.
Why did Igor Thiago start on the bench?
Though they'd got the better of the Bees of late, being unbeaten in the last seven head-to-heads in the English top-flight, Mikel Arteta and his squad wouldn't need reminding how difficult their home fixture was last season when Yoane Wissa's late goal earned a point after Thomas Partey's opener.
Brentford's away form in 2025/26 had been poor, however, with five losses and one win from their six games.
That made the decision to start with Igor Thiago on the bench a very strange one from Keith Andrews, given that the player's 11 league goals have only been bettered by Erling Haaland's 15 so far this season.
The striker was one of five changes made by the visitors, which was their most in successive matches during the current campaign, and their joint most ever in the Premier League (5 v Brighton on Boxing Day 2021).
Merino... again
Before Brentford had even got a foothold in the game, the Gunners went ahead.
Martin Odegaard had already seen a shot blocked before a sumptuous cross from Ben White saw Mikel Merino powerfully connect to head home for his 13th goal in all competitions in 2025 and ninth in the Premier League in the calendar year - no Arsenal player has more in either instance.
No English top-flight player has scored more headers than Merino's eight since the start of last season either, whilst it was the Spaniard's second goal against Brentford in three games, and White's third assist against the Bees.
An 11th goal conceded in the first half meant that only the bottom two clubs, Burnley (12) and Wolverhampton Wanderers (13), had let in more than Brentford.
Arsenal in control
Arsenal's relative dominance was clear for all to see, with the hosts controlling 73% of possession in the opening quarter hour. It might not have always been wonderful to watch, but the Gunners weren't really troubled.
In fact, it wasn't until the 20th minute before the visitors had their first shot, but just like London buses, two more came almost immediately.
Kevin Schade's effort hit the target, though it would be Brentford's only attempt to do so in the entire game, and Arsenal's response was as expected, as they fired off four shots of their own.
Odegaard was marshalling the midfield superbly well, and in creating three chances for his teammates in the opening 45, had effectively been the busiest player on the pitch.
No commitment from Brentford players
Brentford's output was negligible, as evidenced by Dango Ouattara attempting just five passes before the break, with only Ethan Pinnock and Michael Kayode being able to hold their heads high in terms of their passing range.
The former's 96.8% was the best on show for the visitors, with the latter not far behind (95.7%).
Kayode not only contested the most one-on-one duels (15) but also won the most (nine), and it's a shame for Bees fans in attendance that they weren't able to witness such commitment across the board from their players. Kristoffer Ajer, for example, won just one of seven duels contested.
Thiago was one of three players brought on after an hour, though it did little to change the dynamic.
Second goal was inevitable
Oddly enough, despite Arsenal looking reasonably comfortable, Riccardo Calafiori's 66th-minute attempt was their first on target since Noni Madueke's in the 17th.
Still, the hosts poured forward, and Brentford will have been indebted to keeper Caoimhin Kelleher, who had made five saves on the night to keep Arsenal at bay.
Unfortunately for the custodian, his colleagues never looked likely to grab a point, and though it took until injury-time for Bukayo Saka to make the game safe, Arsenal's second goal was inevitable.
Kelleher had got two hands to the England international's shot, but it wasn't enough to stop the ball agonisingly roll over the line.
Game over.
Back to the drawing board for the Bees
When Andrews and his backroom staff take a look back over the game to see where it all went wrong, there'll be a clear slant towards the lack of attacking intensity.
Just one shot on target and six in total, as well as only 13 touches in the opposition box, isn't going to win you football matches.
Ceding two-thirds of possession to one of the best passing sides in the Premier League isn't a surprise, so Brentford needed to be perfect in other areas.
Sadly, double Arsenal's four corners led to nothing, and not winning possession once in the final third tells its own story.
A disappointing night then for the Bees, whereas Arteta and his squad can now look to the fixture against Aston Villa with confidence.
