The Rivals : Chris Evert vs. Martina Navratilova: Their Rivalry, Their Friendship, Their Legacy

In March 1973 two women met on a tennis court in Akron, Ohio.

Over the course of the next sixteen years, together they would change the world.

There has never been a sporting rivalry to match the intensity, longevity, public impact and emotional resonance of the eighty-match-long duel between Martina Navratilova and Chris Evert.

In their long careers Martina Navratilova and Chris Evert played each other eighty times, sixty of those in finals.

For nearly two decades we were transfixed by the struggle between the ice-maiden Chris - blonde, all-American, a nation's sweetheart - and the supreme athlete Martina, a Czech defector, the first outspoken openly gay athlete in female sport, and a woman who wore her heart on her sleeve at all times.

Their careers played out against the backdrop of seismic change in tennis and society, and, together, they helped change the face of women's sport.

Thirty years on from that first meeting, both have become legends.

Based on interviews with both Martina and Chris and those who knew them best, Johnette Howard gives us their remarkable story.