Martina Hingis – 10
Before Roger Federer became a star, Martina Hingis was the first player from Switzerland to win a Grand Slam title. She is also the first Swiss player to be ranked the #1 player in the WTA rankings. Hingis began her professional career in 1994 and won her first Grand Slam title at only 15 years and 9 months in doubles with Helena Sukova at the 1996 Wimbledon. With this title, she became the youngest Grand Slam champion of all time. In 1997, Hingis became the youngest Grand Slam singles champion in the Open Era when she beat Mary Pierce 6-2, 6-2 in the finals at the Australian Open. At that time, she was only 16 years and 3 months old.
In March of 1997, she became the youngest player to be ranked #1 in the world. 1997 was an amazing year for Hingis. Besides the #1 world ranking, she won 3 of the 4 grand slams, including the Australian Open, Wimbledon and the U.S. Open. She went on to win her fourth and fifth Grand Slams at the 1998 and 1999 Australian Opens.
By the time Hingis was 20 years old, Martina had already competed in an extraordinary record 10 Grand Slam finals, winning five of them. She then went on to lose five finals before retiring for the first time in 2003 at the age of 22 due to major injury problems. After a few years, she returned to the field but retired after testing positive for cocaine in 2007. She returned to the court once again and won an Olympic medal in women’s doubles in 2016 before finally retiring from tennis the following year.
Steffi Graf – 9
During her career, Steffi Graf won 22 Grand Slam titles, making her the third most successful tennis player of all time. She started her professional career at only 13 years old and won her first Grand Slam title at 17 years and 357 days when she defeated Martina Navratilova, the reigning #1 ranked player in the world, in the final of the 1987 French Open 6-4, 4-6, 8- 6.
By the time she was 20, she played eight more Grand Slam finals. Her most successful year was 1988, when she became the first player ever to win the Golden Slam because, in addition to winning all four Grand Slam tournaments, she was also the Olympic champion. First, at the Australian Open, she defeated Chris Evert 6-1, 7-6, and in the entire tournament she lost only 29 games. A few months later, Graf played the shortest Grand Slam final ever as she beat Natasha Zvereva 6-0, 6-0 at the French Open after just 34 minutes.
Credit: Getty
At Wimbledon, Graf was down 5-7, 0-2 to Martina Navratilova in the final before coming back to win 5-7, 6-2, 6-1. Graf won her fourth Grand Slam title at the U.S. Open by defeating Gabriel Sabatini 6-3, 3-6, 6-1. She crowned the best season of her career by winning gold at the Olympic Games in Seoul, and again defeated Sabatini 6-3, 6-3.
Graf continued with great results throughout the rest of her career, incuding winning an extraordinary 22 Grand Slam titles. Her last Grand Slam title was in 1999 when she defeated Martina Hingis in the French Open final. She retired in 1999 when she was only 30 years old.
Monica Seles – 9
Monica Seles won eight of her nine her Grand Slam titles as a teenager. Seles is the second youngest winner of a Grand Slam title after Hingis, as she became the youngest French Open champion in 1990 when she beat Steffi Graf 7-6(8-6), 6-4 at the age of 16 years and 189 days. In the following two and a half years, only Graff managed to beat her in the final of a Grand Slam tournament, which happened in 1992 at Wimbledon, and Seles won seven Grand Slam titles in that period. She won three Grand Slam titles in 1991 and three more in 1992. Despite these extraordinary results, she never managed to win Wimbledon.
She started 1993 just as she had the prior two years by winning the Australian Open. Unfortunately, a few months later, at a tournament in Hamburg, Germany, one of the spectators who was obsessed with Steffi Graf stabbed Seles in the back. After that, Seles did not compete for more than two years. When she did return ,she managed to win one more Grand Slam titles at the 1996 Australian Open in 1996.
FUN FACT: Serena Williams has won the most grand titles (23) in the Open era (Margaret Court has the most wins (24 Grand Slam) of all time, including prior to the Open era) out of 33 finals played, but by the age of 20 she had only played in two Grand Slam finals. At the 1999 U.S. Open, she defeated Martina Hingis, while two years later she was defeated by her sister Venus in the same tournament.
Chris Evert – 5
During her career, Chris Evert won 18 Grand Slam titles. She played especially well on clay and she won a record seven titles at the French Open. During her entire career, she won almost 95 percent of the matches that she played on clay courts, including an extraordinary 125 matches in a row. It was at the 1973 French Open that Evert played her first Grand Slam final, where she was defeated by the woman with the most Grand Slam titles of all time, Margaret Court.
Before she turned 20, Evert played in four more Grand Slam finals and won twice. She did that in 1974, first at the French Open and then at Wimbledon, and both times her opponent was Olga Morozova. Evert was dominant during the 1970s and 1980s and went down in tennis history by playing in the most Grand Slam finals of any female player ever (34). She played 56 times in Grand Slam tournaments and was only defeated four times prior to the semi-finals.
FUN FACT: Margaret Court is the player with the most Grand Slam titles of all time (24), although she played a good part of the finals before the start of the Open era. By the age of 20, she had played in four finals and won the title all four times.
Maria Sharapova – 3
Maria Sharapova, from Russia, won five Grand Slam titles during her career and played in 3 finals as a teenager. Sharapova won her first Grand Slam at the 2004 Wimbledon when she beat Serena Williams 6-1, 6-4 in the final. At the time, she was only 17 years and 75 days old. Two years later, she won her second Grand Slam title after defeating Justine Henin 6-4, 6-4 in the U.S. Open final. In her last Grand Slam final before she turned 20, Sharapova was defeated by Serena Williams at the 2007 Australian Open. Sharapova managed to achieve a career grand slam as well as win silver medal at the 2012 London Olympics.