By Matt Majendie

NEW YORK, Aug 30 (Reuters) - Martina Navratilova returned to the scene of some of her most notorious on-court battles at Flushing Meadows for the opening ceremony of the U.S. Open on Monday.

But it was the four-time U.S. Open champion's battle off the court with breast cancer which took centre stage at Arthur Ashe Stadium on a night in which organisers celebrated "those who dream, succeed and inspire."

The 53-year-old, one of the greats of women's tennis, has led a very public fight since being diagnosed with non-invasive breast cancer early this year.

"It's the positive attitude that gets you through life and it is a choice," she said after being the focal point of the opening night celebrations in New York.

"I've always been too much of an optimist where I sort of ignore bad stuff until it sits right there in front of me. I'm saying nothing is going to go wrong and, when it does, that's when I deal with it. That's how I've gotten through life. I think it's done me pretty well."

Navratilova, who plans to climb Mount Kilimanjaro in Tanzania in December, carries a risk of invasive cancer in due course despite having undergone a lumpectomy early this year and radiation therapy that she likened to a prison term.

The Czech-born star also compared her health battle to a tennis career in which she picked up 18 grand slam singles titles amid 167 career wins.

"You have to have a positive attitude to be a champion, to be a great tennis player and you have to be in the moment," said Navratilova.

"I think that's what life is about. And if tennis is not the essence of that, because if you're not with that ball right that split second, if you're just a second late wondering 'oh, did I hit that well?', it's too late."