Arsenal 5 West Ham United 1

The Hammers were shot to smithereens by the Gunners, whose early second half onslaught simply blew Sam Allardyce’s side away at the freezing Emirates Stadium.

Originally scheduled for Boxing Day, this match had been postponed due to London Underground industrial action but, nearly one month on, Arsenal were soon hit by a strike of another kind as Jack Collison volleyed Big Sam’s team into an 18th-minute lead.

But it was to prove a false dawn as Lukas Podolski quickly replied with an unstoppable equaliser to make all-square at the break.

And then a four-goal blast inside the opening 11 minutes of the second half, left West Ham shell-shocked as Olivier Giroud’s double plus strikes from Santi Cazorla and Theo Walcott secured an emphatic victory for Arsene Wenger’s side.

Both teams had frustrating capital connections at the weekend. Despite having had 19 shots, the 12th-placed Hammers had still failed to quash Queens Park Rangers and, following that 1-1 draw, Allardyce made a quartet of changes.

Carlton Cole, Matt Taylor, Collison and Ricardo Vaz Te each came in for the ineligible Arsenal loanee Marouane Chamakh plus substitutes Joe Cole, Matt Jarvis and reported Arsenal target Mohamed Diame.

Sitting in sixth-spot, seven points ahead of the Hammers, Arsenal made two switches from the team that had lost at Chelsea on Sunday as Podolski and Aaron Ramsey replaced Abou Diaby (thigh) and Francis Coquelin (hamstring).

Kicking off without an away goal in 458 minutes on the road, West Ham looked determined to end that sequence and after forcing a couple of early corners and seeing Vaz Te steer a glancing header wide, Big Sam’s side took the lead.

With 18 minutes on the clock, Matt Taylor’s third corner of the night was nodded clear by Giroud to the edge of the penalty, where Collison expertly chested the ball down before letting fly with an unstoppable 18-yard half-volley inside Wojiciech Szczesny’s left-hand post.

While Arsenal had launched a couple of sporadic lightning raids down the flanks, they had up until then only threatened once, when Walcott was robbed by the sliding Winston Reid as he burst through on goal.

But Collison’s opener spurred the Gunners into action and just four minutes after falling behind, they levelled with a strike of comparable quality to the Welsh international’s brilliant opener.

This time, Bacary Sagna probed down the right before passing to Cazorla, who found Jack Wilshere in a more central position and when the midfielder squared to Podolski, Jussi Jaaskelainen was beaten all gloves up as the German international’s stunning 25-yarder fizzed through the icy north London air before ripping into the back of the flying Finn’s net.

Having got one, Wenger’s side went looking for a second and the Hammers rearguard repeatedly found themselves coming under increasing pressure, with Reid and James Tomkins making several clearances with whatever part of their bodies they could.

Ten minutes before the break, Podolski looked all set for a second when he strode on to Kieran Gibbs perfect pass and, although his well-placed shot beat Jaaskelainen, Joey O’Brien was on hand to slide the ball off the line.

By now, West Ham were relying on sporadic counter-attacks of their own and, on 41 minutes, lone-striker Cole had a great chance to give the visitors an interval lead, when Guy Demel’s cross ricocheted off the tussling Taylor and Sagna but the striker’s goal-bound flick cannoned off Szczesny’s shoulder and a covering Thomas Vermaelen slid the ball clear.

The final word of an absorbing first-half almost went to Arsenal, though, when Cazorla arrowed a 20-yard free-kick towards Jaaskelainen’s left-hand angle and, when the keeper clawed the ball out, Giroud’s follow-up from the tightest of angles was bundled behind to keep it all-square at the break.

No matter what Big Sam said to his troops at the interval, it would not have prepared them for the firestorm that was to come at the beginning of the second period.

Just two minutes after the restart, Walcott drove a low corner towards the near post, where Giroud got in front of the tardy Tomkins to flick Arsenal ahead from six yards.

And as the Hammers came to terms with that early setback, worse followed on 52 minutes, when Podolski broke free and crossed into the six-yard box, where Cazorla sent a clever backheel into the net as O’Brien desperately slid in.

An uphill climb suddenly took on mountainous proportions just two minutes later, when the unmarked Walcott arrived at the near post after Wilshere released Podolski from the halfway line and the galloping German had crossed into the dangerzone.

Still Arsenal were not finished, though, and Giroud made it four goals in just 11 quick-fire second half minutes, when he got in front of Reid to convert another low cross into the six-yard box from the pulsating Podolski.

After that, it was a case of damage limitation as Danny Potts, Alou Diarra and Diame each came on for Collison, Reid and Vaz Te, while Wenger – with the game won and one eye on the weekend’s FA Cup clash with Brighton & Hove Albion – introduced Laurent Koscielny, Andre Santos and Alex Oxlade-Chamberlain for Vermaelen, the plundering Podolski and two-goal Giroud.

But after lengthy treatment following a clash of heads with Sagna, poor Potts soon found himself stretchered away with a nasty bout of concussion that was to lead to 12 minutes of stoppage time, while Wilshere forced Jaaskelainen into a full-length save with a low 18-yarder and then Walcott also saw an attempted chip held as ten-man West Ham – who could not wait for the final whistle - restricted the ‘Goals Against’ count to five.

Gunners: Szczesny, Sagna, Gibbs, Mertesacker, Vermaelen (Koscielny 57), Wilshere, Ramsey, Cazorla, Walcott, Podolski (Santos 70), Giroud (Oxlade-Chamberlain 73). Unused subs: Mannone, Arshavin, Jenkinson, Frimpong

Hammers: Jaaskelainen, Demel, O’Brien, Reid (Diarra 63), Tomkins, Collison (Potts 63), Vaz Te (Diame 70), Noble, Taylor, Nolan, C.Cole Unused subs: Henderson, Jarvis, Cole J. O’Neil.

Booked: Vaz Te (43)

Referee: Andre Marriner

Attendance: 60,081