SAN DIEGO — Kevin Durant celebrated his 33rd birthday on Wednesday in San Diego complete with birthday cake and the Brooklyn Nets‘ rookies serenading the star.

Now in his 15th season, Durant says he is “growing every single day” and understands the game more as he adapts and evolves to the changes in the sport. And he says he is “more at ease” and relaxed mentally at this stage of his career as opposed to when he was younger.

“[When you are younger] you want to establish yourself in the league,” Durant said Thursday after the Nets’ practice at their training camp at the University of San Diego. “Sometimes you may overthink it and may think too much about reactions and opinions of others because you are on the journey to perfection. But start to relax a little bit and understand what this is about and understand the long game, and it definitely made my mental a little bit more at ease coming to the gym every day and not focusing on that stuff.”

As Durant prepares for his second season on the floor and third overall with the Nets, he and teammates Kyrie Irving and James Harden start camp with enormous championship expectations. But Durant says the pressure will not affect this veteran group assembled to win it all.

“Yeah, outside pressure don’t really matter much,” Durant said when asked whether pressure is even an issue at this stage in his career. “I think we all internally put pressure on ourselves because we hold ourselves to a high standard and you want to play well every time you step out there; that is just who we are as competitors.

“As far as the outside noise, no disrespect for you guys [in the media], for our families, friends and even our fans expecting us to do so much — if we don’t live up to those, at the end of the day, it doesn’t matter. But we want to come out and play a great brand of basketball every night and we hold ourselves to that standard. I expect us to come out there with some swagger and some intensity. But outside noise shouldn’t matter much to this group.”

Durant is focused on the daily details such as his approach to every practice rep. He also says he has tried to adapt his game over time to how the sport is being played and how opposing coaches have tried to defend him.

“It’s just the evolution of the game,” said Durant, who started his career in 2007-08 in Seattle at age 19. “I’ve played against different schemes and strategies out there. Coaches are working nonstop to try to figure out a new way to play the game, and I feel like I have to be on that same page. I got to sort of catch what’s going on in the game of basketball just like a coach would, and I think that’s what my development is.”

“It went from playing a slower pace when I first got to the league to now playing a fast pace, 3-point style,” he added. “So I think I’ve adjusted to that. Whatever happens next, I’ll be ready.”

At 33, Durant is ready and more at ease.

“I really feel like I have been growing every single day and I am starting to understand the game a little bit more,” Durant said. “I kind of simplified it for myself. I try not to chase anything outside of just being the best that I can be on the floor.

“I really try to approach every rep as trying to be the best I can be and everything else outside of that will take care of itself, so the results, if I prepare the right way, will handle themselves. Yeah, it’s made me at ease a little bit.”