Martinez returned to the New Bucks Head earlier this summer following a spell last term in which he did not play a competitive minute.
The Bucks are on the hunt for another shot-stopper but the 25-year-old has started all (at time of writing) of the Bucks' pre-season games and is not willing to give up his spot easily.
"I'm feeling really good, pre-season has gone really well," said Martinez, who has also been at Solihull Moors.
"The lads are looking to just stick to the messages the gaffer is giving out.
"Myself, I feel a lot fitter and sharper. I've just got to build on my fitness, keep going, get the games in, and hopefully come the start of the season I'll be ready – fit and sharp."
Jono Brown and Callum Preston have also featured between the sticks for Telford in pre-season, and the club are also believed to weighing up a move for another young goalkeeper.
But Martinez has a strong working relationship with Bucks boss Gavin Cowan and goalkeeping coach Darren Acton, having worked with them both at Solihull too.
On being the club's go-to goalkeeper, he said: "Of course, that's my main aim this season. That's the reason I came back.
"Gav and Acco, I really trust. For me it's about getting my head down, pushing for the No.1 spot, and hopefully doing well this season – getting game time.
"I've felt really comfortable. When called upon, I've felt good.
"The games are coming thick and fast now so I've got to keep going, to be ready for the start of the season."
Martinez is impressed by the squad Cowan has got together.
He played with Darryl Knights and Theo Street at Solihull and knows skipper Shane Sutton and midfielders Jon Royle and Henry Cowans, among others, well from his first Telford stint.
"The squad is really good, everyone gets on," added Martinez.
"I'm looking forward to this season. We just want to get on with it."