The Gunners never really got going on Thursday evening and struggled to create anything of note until the latter stages after Keane Lewis-Potter cancelled out Noni Madueke’s opener.
The onus was on the league leaders to take all three points from this fixture after Manchester City had cut the gap to four points following their 3-0 win over Fulham on Wednesday evening.
Neither side could really find sight of the goal for the majority of the opening stages, but Brentford’s Igor Thiago came closest to opening the scoring with a powerful header from point-blank range that David Raya reacted brilliantly to keep out.
Arsenal looked vulnerable to Brentford’s relentless pressing to win the ball back high up the pitch, forcing early mistakes from Gabriel and Declan Rice as Mikel Arteta’s side tried to catch up with the tempo.
Mikel Arteta’s side looked jaded and struggled to keep up with the pace of Brentford’s play, as further errors in possession from Piero Hincapie and Leandro Trossard saw a rare pair of chances pass by.
Brentford’s threat from set pieces grew throughout the first 45 minutes. Michael Kayode’s extraordinarily long throw tactic put David Raya and the Arsenal backline under sustained pressure, but Rice was twice on hand to clear the danger.
The Gunners came out for the second half with much more intensity. Martin Odegaard replaced Eberechi Eze as the latter was hooked at half-time for the second successive game he has started in (2-1 loss to Aston Villa in December).
Odegaard was then presented with an opportunity to give his side the lead, but the familiar sight of the Norway captain’s lack of composure in front of goal reared its head again as he blasted the ball well over the bar.
As Brentford stayed strong, Arsenal tried everything in their power to win the ball back high. Viktor Gyokeres's much-improved hold-up play came to light once again, but Arsenal were missing the killer instinct once again.
The league leaders then found themselves ahead on the stroke of the hour mark as Noni Madueke nonchalantly nodded home Piero Hincapie’s looped cross after Arsenal had regained possession in the Brentford half.
Typically of Madueke, the former Chelsea winger’s finish came off in unorthodox fashion. The ball seemed to bounce past Kelleher in slow motion as Madueke prepared to wheel away in celebration.
Nonetheless, Arsenal had their advantage. Brentford came close to responding almost immediately when Keane Lewis-Potter found himself unmarked at the back post but could only guide his header wide of David Raya’s goal.
Brentford remained a threat in transition. Christian Mosquera, deputising in place of the injured William Saliba, was held off too easily by Igor Thiago as the Brazilian striker broke into space prior to firing straight at Raya.
But after banging on the Arsenal door for a considerable period following Madueke’s opener, Brentford restored parity when Sepp Van Den Berg got on the end of Kayode’s monster throw before flicking the ball towards the back post for Lewis-Potter to head past Raya.
Arsenal rallied to find a winner and regain their six-point lead over Manchester City at the top of the Premier League but struggled to bring the likes of Gyokeres and the returning Bukayo Saka into the game after the Arsenal star was brought on to replace Madueke.
Igor Thiago proved to be a thorn in Arsenal's defence all evening and won another duel with Mosquera before racing through one-on-one with Raya.
But the Arsenal defender recovered brilliantly to slide in and take the chance away from Thiago as the ball flew out of play on the far side.
As the game was stretched, Brentford still looked the more likely. Arsenal looked tired, short of ideas and like a team desperate for a long rest, as their legs weakened by the minute.
In the second minute of stoppage time, Thiago was presented with yet another opportunity to snatch a late win, but the Brentford striker lost all composure and fired well over the bar from an acute angle.
Substitute Gabriel Martinelli might have won it for Arsenal with virtually the last kick of the game, but his tame effort was smothered by Kelleher as Arteta stood on the sidelines in disbelief.
The basketball nature of this game might live long in the memory for both sets of fans, but this is another failed Arsenal response to a Manchester City win.
Six points now becomes four. The title race – whether Arsenal fans like it or not – is most certainly on.