Andy Roddick opens up on which of his children has his "fiery" personality, how his wife Brooklyn Decker makes him a better person, and dealing with the "phenomenal experience" of fatherhood

Andy Roddick, one of the greatest American men to have picked up a tennis racquet, recently shed light on the lesser-known aspects of his private life in an interview with the New York Post.

The former World No. 1, who married actress and model Brooklyn Decker in 2009, has two children -- a six-year-old son named Hank and a four-year-old daughter named Stevie. Among the two, Roddick revealed it was his daughter who takes after him the most, especially with regards to his "fiery" personality.

"I’d say our daughter is a little bit more fiery, but Brook’s pretty fiery too. I’d say it’s a decent mix," Roddick said. "I think other people around us would say my daughter is more like me."

The 39-year-old has taken to fatherhood like a fish to water, although he admitted it does test his patience at times. Despite that, he is glad to have become a parent, a "phenomenal" experience that keeps him honest in his day-to-day life.

"You become better. It kinda tests your weaknesses … you know, patience … but it’s just such a phenomenal experience," Andy Roddick said. "It’s hard to describe. But I think it keeps you honest daily."

The former US Open champion also touched on how his wife Decker has made him a better man, remarking that her toughness and independence continue to impress him to this day.

As someone who is "hyper-motivated" all the time, Roddick is glad that she also has the same attitude, since it has helped create a strong sense of mutual respect between them.

"She makes me better. She is tough, she’s independent, she’s self-motivated. All those things were very important to me when we met, and even now," Roddick said. "I don’t know that I’d want someone to sit around with and say like, 'What are we gonna do today?' I think we’re both pretty hyper-motivated all the time, and I think that creates kind of a base element of respect for each other."

"I’m not a fan of it, I want to stay as young as possible" - Andy Roddick on turning 40 soon

As he edges close to turning 40, Andy Roddick wished he could stay as young as possible instead

Come August 30, Andy Roddick will turn 40. While the American remarked that he is never usually bothered by birthdays, he is not particularly thrilled to see himself move past his 30s.

If he could have his way, the former US Open champion would stay forever young instead, an avenue that is unfortunately unavailable to him.

"I’ve never really been bothered by birthdays. I think this is the first one where I’m going, “Man, have I lived more life than I haven’t lived for the first time?“ I’m not a fan of it," Roddick said. "I want to stay as young as possible."