Watch: Giroud beauty caps crucial Arsenal win

Olivier Giroud, you beautiful man.

The stately striker made it 3-0 for Arsenal Wednesday against West Ham courtesy of a delightful curler after fellow second-half substitute Alex Oxlade-Chamberlain made a dashing run towards the Irons' area seven minutes from time.

Theo Walcott scored his second in as many games as Arsenal became the first Premier League side to score a century in all competitions after Mesut Ozil opened the scoring in the 58th minute.

It was a deserved result for the home side who again appeared an inspired lot after months of dire play, with Arsene Wenger's side combining intelligent runs with quick passing to befuddle West Ham's defenders.

On the contrary, Slaven Bilic's side was short on ideas.

Andy Carroll got next to no service and Manuel Lanzini was uncharacteristically inconspicuous.

Not bad for a side that had won just one of its previous six league matches and was forced to start third-choice shot-stopper Emiliano Martinez and an error-prone centre-half pairing of Shkodran Mustafi and Gabriel.

The scoreline complimented the Irons after Martin Atkinson missed stonewall penalties where Arthur Masuaku bodied Walcott and moments before the final whistle when Sam Byram clumsily stomped on Nacho Monreal's foot in the area.

With the result, the Gunners vault Manchester United for fifth place in the table on 54 points, four adrift with a game in hand on Manchester City.

Matters could have been ever more fortuitous for Arsenal's top-four chase had Tottenham not fought back from behind to beat Swansea City.