Wilshere shrugged off an early ankle knock to play an hour of the 1-0 win over Denmark at Wembley on Wednesday night, which was the final friendly before England manager Roy Hodgson names his provisional World Cup squad.
The 22-year-old accepts dreams of a summer in Brazil will now depend very much on what all players can produce on a regular basis at club level.
"We have all been working hard in training trying to impress the manager, but at the end of the day, it is your club form which will get you in," he said.
"These next two months are crucial, it is a big time of the season and then when the England squad is announced, you can only perform to the best of your ability."
Wilshere revealed he suffered no ill-effects from a heavy knock to his ankle in a challenge with Denmark's Liverpool defender Daniel Agger during the first half.
The Arsenal midfielder was substituted after an hour and replaced by Southampton's Adam Lallana, whose cross set up Daniel Sturridge for a late headed goal to finally beat Kasper Schmeichel, the Leicester goalkeeper.
There was, though, no major injury scare for a player set to be crucial to Arsenal's run-in, which continues with an FA Cup quarter-final against Everton on Saturday.
"It is a bit sore, but just a bruise. I have had a scan already and I will be alright," Wilshere told reporters.
Hodgson, meanwhile, maintained Wilshere - who has been a through a string of injury setbacks - was never scheduled to play the whole match.
"It was always the plan to replace him just after half-time, not least of all because Arsenal have some important games coming up, a lunchtime kick off (against Everton on Saturday) and then Munich (away in the Champions League)," the England manager said.
"We had that in mind not to keep him on the field for too long."
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- England manager