Theo Walcott reckons the competition among the wingers in the England squad is bringing the best out of him in the battle for a World Cup spot.[LNB] England head coach Fabio Capello is facing a selection headache in terms of whom to select from Walcott, Aaron Lennon, Adam Johnson and Shaun Wright-Phillips for his final 23.[LNB]The Arsenal player started Monday's clash with Mexico at Wembley, with Lennon and Johnson entering the action as second-half substitutes.[LNB]And Walcott showed a willingness to track back as well as making some of his trademark runs and crosses.[LNB]He said: "The boss wants me to stay out wide, to be an outlet with Stevie G (Gerrard) coming inside.[LNB]"But I also did a lot of tracking back. It is not always about getting forward and, when I could, I did (get back).[LNB]"People saw a different side of me, going forward and back.[LNB]"But it's not just about me. There's Aaron and Adam as well. It is great competition to have.[LNB]"It is a great thing having competition, especially in my position, because it gets the best out of you. Aaron, Shaun and Adam are among the best players in England.[LNB]"It is a headache for the manager, but a nice headache, because there are fantastic options.[LNB]"It was a nice little boost getting the chance to start in the number seven shirt, especially at Wembley with the tremendous support. It shows I had been training quite well."[LNB]Walcott reckons there are many players who possess the kind of pace he is able to demonstrate.[LNB]He said: "There are so many quick players out there. You saw Aaron show what he can do when he came on in the last few minutes against Mexico.[LNB]"A lot of players use their pace at different times in the game and it is not always about knocking the ball past someone and running. It is easier said than done."[LNB]Walcott does not feel being in the first XI against Mexico means he is certain to start in the World Cup.[LNB]He said: "It was just a friendly game even though we treated it as a competitive game.[LNB]"It was just a chance to go out there and express yourself but it didn't reflect anything about the World Cup.[LNB]"The most important thing for me is to train well and, if I train well, get the chance to play.[LNB]"I just enjoy playing football. I just want to go out there and show what I can do.[LNB]"There have been ups and downs in my career and you are going to face that.[LNB]"You can't play well for the whole 90 minutes and the whole season. It is just one of those things. Things go your way sometimes and sometimes they don't."[LNB]Meanwhile Walcott believes he will reap the rewards of David Beckham's involvement at the World Cup if he does get the nod from Capello to go to South Africa.[LNB]David Beckham has been fantastic for me especially, but not just me, so many players," Walcott said.[LNB]"He gives you that extra boost. If you see someone who has won so many things, you get the best out of the players and you want to be part of that.[LNB]"Just having him around (at the World Cup), giving you advice, one of the best crossers of the ball, can only help.[LNB]"It's a shame his injuries mean he won't have a chance to play in a last World Cup and he is a big miss.[LNB]"But hopefully he is going to help the players by being around and boost the spirits of the players. Having him there can only help."[LNB]Walcott has already taken on board plenty of tips imparted to him by Beckham as he prepares for his second World Cup, providing he is named in the final 23.[LNB]He said: "The most important thing Becks says is just enjoy it, play with no fear, and if you are young and play with no fear, the best comes out of you.[LNB]"He has always also told me to deliver the ball into the space and, if there is no-one there, it is not your problem because someone should get on the end of it."