WEST BROM 0

ARSENAL 4 Tierney (22), Saka (28), Lacazette (60, 64)

Sad West Brom caught the Gunners on one of their best nights of the season, with Mikel Arteta’s side breathing life into a campaign which was going off the rails just a few games ago.

Hector Bellerin and Saka tested Sam Johnstone inside the opening 10 minutes to set the tone for a dominant first half.

Pierre-emerick Aubameyang also almost marked his 100th Premier League appearance with a goal but just failed to turn Saka’s teasing low cross in at the far post.

Albion’s only chance came when Matt Phillips’ fired straight at Bernd Leno after Matheus Pereira’s cute pass.

But Arsenal grabbed the lead and total control after 23 minutes when Tierney proved why, when fit, he is such an asset.

The full-back twice beat Darnell Furlong to embarrass the defender on the left and cut inside before firing high past Johnstone from 15 yards.

Five minutes later it was 2-0. Emile Smith Rowe swapped passes wth Saka and Lacazette before being slipped through by the Frenchman to cross for Saka, who had continued his run unmarked, to tap in.

Johnstone needed to turn Lacazette’s cross over after it hit Grady Diangana and the keeper denied Lacazette two minutes before the break after the striker outmuscled Branislav Ivanovic.

The hosts needed a response and Callum Robinson fired in after Pereira hit the post following the restart only for the offside flag to halt their celebrations.

But Arsenal wrapped up the points with two more quickfire goals from Lacazette.

Saka again caused chaos for the first when his 61st-minute cross was turned onto his own post by Semi Ajayi, who then blocked Smith Rowe’s follow-up strike, but Lacazette gobbled up the rebound.

The second, after 64 minutes, was equally as simple as the striker converted Tierney’s cross from close range.

Johnstone stopped Aubameyang adding a fifth late on and saved from Willian before Leno denied Rekeem Harper a stoppage-time consolation.