A 5-1 win is generally a reason to celebrate the success of the squad you already have, but Arsenal fans have seen too many false dawns to get carried away just yet.
There might even be Arsenal fans out there now who are a little worried that their manager might choose not to enter the transfer market this month on the strength of the showing his team delivered on Wednesday night.
There are still problems in the squad at the Emirates, and these will need to be addressed to give Arsenal the best possible chance of claiming a Champions League place in the second half of the season. The excellent win over West Ham provided a boost for the club after two losses to their rivals, but it shouldn't stop Arsenal strengthening in the next few days.
The win also demonstrated the value available in the transfer market. Central to the win was the efforts of Santi Cazorla, Olivier Giroud and Lukas Podolski. Arsenal's three main summer signings produced four of the goals and three of the assists in the match, with Podolski standing out in particular.
The impact of these three players on the success of Arsenal's attack has been integral to the side this season, and Wenger must now look to bolster his defences in a similar way. In midfield, a defensive midfielder is required to compete with the injury prone Diaby, and their defence could also use strengthening, as a couple of injuries could see Sebastien Squillaci and Andre Santos take to the pitch once again.
Arsenal won't want to spend the amounts they did on Giroud, Podolski and Cazorla again this month, but there are options out there for reasonable prices. They could have entered the race for Yanga-Mbiwa, who Newcastle picked up for £6.7 million, and they should be in the hunt for Moussa Sissoko and Mohamed Diame.
Arsene Wenger loves to show faith in the players he already has in his side, but last night's win demonstrated how important signing new players can be for the club. Having strengthened his attack in the summer, Wenger should be looking to bring in players to shore up his side's defences in the next week. If he does so, they might nudge ahead of their rivals in the race for a Champions League place.
image: © Ronnie Macdonald