Just as against Chelsea last weekend Arsenal were slow out of the blocks, even going 1-0 down to a Jack Collison strike after 17 minutes; but just as at Stamford Bridge Wenger found the right words at half-time to inspire his team.
Four goals in 10 stunning minutes completely turned the game around and changed the entire atmosphere of a club and a team that has been suffering from a lack of belief this season.
Lukas Podolski, just back from injury, provided perhaps the most telling contribution; because having scored Arsenal’s equaliser with a thunderbolt in the first half, his second-half performance included a hat-trick of assists.
A delighted Wenger said: “We got a good response. In the second half we created chance after chance and played at a very high pace. It was great movement, great quality in our final ball.
“I never felt the players didn’t know how important it is. I was more worried that they were sometimes inhibited in the recent big games from the start. But this team has a fantastic mentality and good quality. That’s what we want to show until the end of the season now.”
Having got to half-time on level terms Arsenal went ahead through Olivier Giroud, the Frenchman who has been doing everything except scoring in recent weeks, when he produced an excellent left-foot finish from a Theo Walcott corner on 47 minutes.
Santi Cazorla was next - cleverly backheeling a low Podolski cross into the net after 53 minutes, followed swiftly by Walcott a minute later - the winger arriving at pace at the far post to drill home a Podolski cross at the end of another sweeping move.
The fifth was yet another clever finish from Giroud and yet another cross from Podolski, fed by the inspirational Jack Wilshere who enjoyed another excellent evening. Suddenly the old Arsenal were back - even if it had taken a half-time dressing down to make it happen.
Giroud, who desperately needed a goal, must surely be revived by his double strike here and on a near perfect night, the only worry concern was Arsenal’s wobbly defence, which looked decidedly nervous at set pieces in the first half when they conceded from a corner - a shot drilled home by Collison after Giroud failed to clear - and found Carlton Cole difficult to deal with.
This result doesn’t move Arsenal up - they’re still sixth; but they’re in a better place than they were Sunday.
ARSENAL: Szczesny 6, Sagna 6, Mertesacker 6, Vermaelen 6 (Koscielny 57; 6), Gibbs 6, Ramsey 6, Wilshere 8, Cazorla 7, Walcott 7, Giroud 8 (Oxlade-Chamberlain 73), Podolski 9 (Santos 70). Subs: Mannone, Arshavin, Jenkinson, Frimpong.
WEST HAM: Jaaskelainen 5, Demel 6, Tomkins 6, Reid 5 (Diarra 62; 6), O'Brien 5, Noble 6, Nolan 6, Collison 7 (Potts 62), Taylor 5, Carlton Cole 7, Vaz Te 5 (Diame 70). Subs: Henderson, Jarvis, Joe Cole, O'Neil.
Referee: Andre Marriner