The question has been asked time and time again. Martina Navratilova or Steffi Graf? Which is the greatest female tennis player of all time? My view is this: Graf was the better in singles, while Navratilova was on top in doubles and mixed doubles.
That being said, I don't know if anyone will ever dominate all three like Navratilova did. At the tender age of 19, she reached her first two Grand Slam singles finals in 1975. She lost both tournaments (Australian Open to Evonne Goolagong, French Open to Chris Evert).
Martina won her first Grand Slam singles title at the 1978 Wimbledon, this time around getting the better of Evert. The victory earned her the World No.1 ranking for the first time in her career. The next year, she successfully defended her Wimbledon title, defeating Evert once again.
In 1981, she won her third major title by defeating Evert once again—this time at the Australian Open final. She won both Wimbledon and the French Open in 1982 to add to her trophy case. The first major tournament of 1983 was a big disappointment for the former Czechoslovakian.
At the time, the Australian Open was held in December. No title at the French, but she'd win the three remaining Grand Slam singles tournaments of the year. Martina's loss at the French Open was her only defeat in singles competition that year. She finished with a record of 86-1—the best ever winning percentage for a tennis player.
The French Open, Wimbledon and the U.S Open were all captured by Navratilova in 1984. At the Australian Open, she had a chance to win all four titles in the same year. However, she lost in the semifinals to Helena Sukova and her 74-match winning streak was gone. It's still a record for professional tennis players today.
The left-handed hitter won all four Grand Slam women's doubles titles in 1984 with Pam Shriver. This pair won a 109 straight doubles matches between 1983 and 1985 (another record). Navratilova was the name beside the World No.1 doubles player spot for over three years in the 1980's.
From 1985 to 1987, Martina reached the women's singles final at all 11 Grand Slam tournaments played during those years, winning six of them. During that time, she extended her Wimbledon run to six straight titles. Then, Steffi Graf entered the scene in 1987, defeating Navratilova in the French Open final.
That same year (1987), she defeated Graf in the Wimbledon and U.S Open finals. Graf's consistent play through the year allowed her to grab the World No.1 before the end of the year. Both women would meet again in the 1989 finals of both Wimbledon and the U.S Open. Graf was the victor on both occasions.
Regardless of the significant age difference between the two women, Navratilova won nine of the 18 career singles matches with Graf and five of the nine Grand Slam singles matches the two squared off in. Her final Grand Slam singles glory came in 1990, defeating Zina Garrison in straight sets to claim a record-breaking ninth Wimbledon singles title.
She still appeared in two more Grand Slam singles finals—the 1991 U.S Open final and the 1994 Wimbledon final. On both occasions, she came up a little short of victory.
Over her career, Navratilova won 18 Grand Slam singles titles, 31 Grand Slam women's doubles title (all-time record), and 10 Grand Slam mixed doubles titles. Her last title came with Bob Ryan in mixed doubles at the 2006 U.S Open final at the age of 49. That's unbelievable.
Martina had a left-handed serve and superior volleying skills. The huge advantage in her game was her excellent fitness and conditioning though. She raised the women's game to new levels with her power and aggression.
Navratilova is just one of three women to have won every Grand Slam title in singles, doubles, and mixed doubles competition (referred to as the Grand Slam "boxed set"). Her 167 singles titles and 177 doubles titles are both records in the open era. She also holds three of the six longest winning streaks in women's tennis history.
Billie Jean King said the following about Martina Navratilova in 2006:
"She's the greatest singles, doubles and mixed doubles player who's ever lived."
Seems to be true. I doubt anyone will ever overdue her great stats in all three competitions.