Arsenal ease out of their early season struggles to thrash West Brom 4-0 and cement the Midlands team as one of the relegation favourites.<br/> Kieran Tierney's stunning solo goal opened the floodgates, Bukayo Saka rounded off a brilliant team move and Alexandre Lacazette scored twice to make it three wins in a week.<br/> The Arsenal turnaround came after seven Premier League games without a win had left the Gunners looking nervously, if unlikely, down at the relegation places. Meanwhile, Albion, managed by newly-hired Sam Allardyce, who brought with him a record of never having a team relegated, have now conceded nine times in two games. West Brom are yet to win in four games since Allardyce took charge and the former England manager needs to quickly instil the defensive discipline he has made his trademark if the Baggies are to have any chance of survival. Just over a week ago Allardyce said Arsenal were in a battle against the drop, but Mikel Arteta's decision to finally put faith in his crop of talented youngsters has turned his side's season around. Saka was again the shining light, while Tierney and Emile Smith Rowe also impressed. Arsenal's poor run was principally caused by a struggle to score goals, but they were a threat from the off despite the treacherous conditions. Sam Johnstone denied Hector Bellerin and Saka inside the first 10 minutes, but he was powerless to stop Tierney's stunning opener on 23 minutes. The Scotland international left Darnell Furlong trailing in his wake before cutting inside on to his weaker right foot and curling into the top corner. Arsenal's second was reminiscent of their flowing football at the height of the Arsene Wenger era as Saka fed Lacazette, whose brilliant pass played Smith Rowe in behind the West Brom defence and he squared for Saka to tap into an empty net. The one way traffic continued after the break and some comical West Brom defending led to the third as Semi Ajayi smashed a dangerous cross off his own post and the ball broke to Lacazette to apply a simple finish. Moments later another raid from Tierney down the left teed up Lacazette for another finish from point-blank range. Arsenal are now six points off the top four. West Brom remain six points adrift of safety and showing little sign of life since Allardyce's arrival.