Martinez said the competition for places and depth within the Merseyside club's squad had pushed the foursome to excel in the Premier League this season.
"John Stones is a modern centre half – he is not a young centre half with potential," Martinez said.
"He is as good as it gets at that age. Ross Barkley? We have all seen the combination he has of incredible physical and technical attributes.
"Romelu Lukaku who has scored 51 Premier League goals before the age of 23 and Gerard Deulofeu, when he is at that sort of level, he is as good as it gets. Then you need to understand the support of the experienced players like Gareth Barry and Tim Howard, you need that to be a consistent team.
"Young players with talent is not enough. I'm delighted to have that balance in the squad and it is big enough to have that competition. With the squad that we have, it is that competition for places and the way we train, that intensity allows players be at their best."