Mikel Merino has been converted from a central midfielder to the fulcrum of Arsenal's attack due to injuries to Viktor Gyokores, Kai Havertz and Gabriel Jesus.

The Spain international has risen to the challenge with five goals this season, including the first-half header that opened the scoring at the Emirates Stadium.

It was the second successive game that Merino delivered a vital contribution to Arsenal's title challenge after his equaliser at title rivals Chelsea on Sunday.

Thanks to Merino, and Bukayo Saka's strike in the closing moments, Mikel Arteta's side moved five points clear of second-placed Manchester City, who won 5-4 at Fulham on Tuesday.

Arsenal are unbeaten in their last 18 games in all competitions as they chase a first English title since 2004.

After finishing as Premier League runners-up for the last three seasons, the Gunners are showing the priceless ability to grind out results when they are not at their best.

After coming from behind to avoid defeat at 10-man Chelsea on Sunday, Arteta was concerned about the potential for an emotional and physical hangover from his players against Brentford.

Arteta called for Arsenal fans to turn up "like animals" at the Emirates Stadium to help roar his team to victory.

In the end, the atmosphere was more nervous than Arteta would have liked as Arsenal clung to their lead, but far more raucous days lie ahead if his team retain pole position in the title race.

Dropping Saka, Eberechi Eze and Jurrien Timber to the bench to keep them fresh ahead of the hectic Christmas schedule, Arteta brought in Martin Odegaard, Noni Madueke and Ben White, who made his first league start since August.

- Arsenal grind it out -

Arsenal were without injured centre-backs William Saliba and Gabriel Magalhaes, but Brentford boss Keith Andrews did Arteta a favour by benching prolific Brazilian forward Igor Thiago and the Gunners kept their first clean-sheet in five matches.

Andrews deployed a back five in a bid to frustrate Arsenal but it took Merino just 11 minutes to breach the visitors' defence.

Madueke's clever back-heel allowed White to whip a cross towards Merino and the Spaniard timed his run perfectly to guide a header past Caoimhin Kelleher from six yards.

Arsenal pressed hard for a second and Madueke's low drive was repelled by Kelleher before White fired into the side-netting.

Brentford nearly snatched an equaliser completely against the run of play when Kevin Schade's thumping header from a corner was superbly tipped onto the crossbar by David Raya.

Arsenal have conceded just two goals at home in the league this season, but their defensive injury problems mounted just before half-time when Cristhian Mosquera limped off.

Mosquera's departure knocked Arsenal out of their stride and the second half became a war of attrition as the Gunners tried in vain to recapture their first half swagger.

Arteta responded by introducing Saka and Eze, a move that immediately revived Arsenal as Riccardo Calafiori's blast was well saved by Kelleher.

Declan Rice tested Kelleher with a 20-yard rocket that the goalkeeper pushed out to Merino, who poked wide from close range.

Rice was forced off in the closing stages in a worrying sight for Arteta.

Saka ensured Arsenal wouldn't miss the England midfielder as he raced clear to wrap up the points with a stinging strike that Kelleher could only parry into the net.