But Lambert, 31, who netted against Scotland and Moldova, insists he will not lose any sleep if he misses the cut.
Lambert said: "I am under no illusions and know how hard it will be to get in the squad. It is a long shot.
"It is something I will be fighting for and I know I have to do well for Southampton.
"I know I need to score goals but even that might not be enough to get me the nod.
"It might be a shoot-out between me and Andy Carroll. I'm not going to lie, I think that is one of the major possibilities.
"I will focus on my game and when Andy is back from injury he will be raring to go as well, so it's up to Roy Hodgson to decide.
"If I get to the World Cup it would be the highlight of my career, but three months ago I never even had a cap."
For the big stories and the banter follow us on Twitter: @tribalfootball