Martina and Chris: This longtime gay-straight alliance on "Oprah" today...

When I spoke with Martina Navratilova a few weeks ago, she was leaving for Chicago the next day to tape an episode of "The Oprah Winfrey Show" on extraordinary friendships. Appearing with her on the show would be Chris Evert, the greatest rival of her pro tennis career. The show airs today (3 p.m. in LA, check your local listings for elsewhere).

The Navratilova-Evert relationship is fascinating on many levels. In terms of pure sports, few rivals have competed so many times (80 matches between 1973 and 1988) and nearly finished dead-even (Martina edged Chris 43-37 head-to-head). Each won 18 grand slam titles and between them, held the number one ranking from 1975 through 1987 with only Tracy Austin breaking their stranglehold for a brief time in 1980.

I watched so many of their classic matches with the best being Chris' wins over Martina in the 1985 and 1986 French Opens and Martina's victories over Chris in the 1988 Wimbledon semifinal (see video below), 1984 US Open final and 1981 US Open seimifinal. Both were at their best in these riveting three-set thrillers.

And here's a few points from their 1975 French Open final won by Evert:

But enough of the tennis part.

As these two tried to beat each other's brains out on the court, off the court they were almost always pretty tight except for a brief period in the early 80s. They were pals in the mid-70s when Martina defected to the US and win the French and Wimbledon doubles together and when their rivalry was at its peak, they spoke with respect for each other and always consoled each other after a match no matter which one won.

Martina was couragous enough to come out publicly as a lesbian almost 30 years ago when it was a far more difficult thing to do - especially on the world stage. She deserves everlasting credit and respect for blazing that trail and for continuing to be a leader and outspoken activist.

Chris, during her playing career, was perceived as America's sweetheart which such nicknames as "Cinderella in Sneakers" and "Chris America." She was also the world's top-ranked player when Martina came out and when Billie Jean King was outed by a vindictive ex-lover who filed a palimony suit. Chris very publicly supported both women at that time and remained so.

Billie Jean told me a few years ago that it is exactly that kind of support from top stars that is needed in men's sports if male athletes are to ever feel comfortable coming out during their playing careers.