7 ladies who have won 3 Majors in a single season in the Open Era

Four of the biggest tournaments in tennis are the Australian Open, French Open, Wimbledon and US Open. Each tournament is referred to as a "Slam" or "Major" and offers 2,000 points to the winner. The WTA tour has thus far produced 55 players who have won at least one Slam.

Tennis became much more competitive at the onset of the Open Era when amateurs and professionals played together. Winning multiple Slams in a single season has become an extremely difficult feat. Let's take a look at seven women in the Open Era who have won three of the four Majors in a calendar year.

#1 Margaret Court

Court At The 2017 Australian Open

Margaret Court has won three Majors in a calendar season on four occasions - twice before and twice since the Open Era began. One of only three players to win a box set (winning a singles, doubles and mixed doubles title at each slam), the 24-time singles Slam winner won three Majors in a row in 1969 and 1973. She achieved a much greater feat of winning the calendar Grand Slam (all four Majors) in 1970.

In both 1969 and 1973, the Slam that Court failed to win was Wimbledon. Her opponents in the finals were Ann Jones and Chris Evert respectively. Court's opponents during her victorious run in the 1969 and 1973 Major finals were Billie Jean King, Ann Jones, Nancy Richey, Evonne Goolagong (twice) and Evert.

#2 Billie Jean King

Billie Jean King

Billie Jean King, along with Margaret Court, was the most dominant player of the late 60s. In 1972, King chose not to participate at the Australian Open. Frank Deford, who authored King's biography, said the reason for her not participating at the Happy Slam was because she felt that back then that it was a "minor-league" tournament. In 1972, Court was absent for a significant part of the season due to her pregnancy. This paved the way for King to increase her slam tally. Ironically, King won just two of the first 10 tournaments she entered that season.

The turnaround came during the clay season, where King won the French Open without losing a set. In the process, she completed the career Slam. King later won the Wimbledon final against Goolagong. King did not win any of the warm-up tournaments leading up to the US Open. However, she managed to win the US Open without dropping a set.

#3 Martina Navratilova

Martina Navratilova dominated women's tennis between 1982-86

Martina Navratilova is one of the greatest tennis players to have ever played the sport. She dominated women's tennis between 1982 and 1986. Between 1982 and 1984, Navratilova lost only six matches.

In 1983, Navratilova won Wimbledon, the Australian Open and the US Open, defeating Andrea Jaeger, Kathy Jordan and Chris Evert in the finals. Navratilova's lone defeat in 1983 came in the fourth round of the French Open against Kathy Jordan.

Navratilova entered the 1984 Australian Open while on a 70-match winning streak. However, in the semifinals, she lost to ninth seed Helena Sukova. Navratilova's 74-match winning streak is the longest in the Open Era. In the remaining Slams that season, Navratilova defeated her arch-rival Chris Evert in all three finals.

#4 Steffi Graf

Steffi Graf at the Wimbledon Lawn Tennis Championship

Following her Golden Slam run in 1988, Steffi Graf won three Majors in a single season in 1989, 1993, 1995 and 1996. Graf was most often challenged by Martina Navratilova, Arantxa Sanchez Vicario, Gabriela Sabatini and Monica Seles in the finals.

Along with Court, Graf is the only player to have won at least three Majors in a single season five times.

#5 Monica Seles

Monica Seles won eight Slams before the ae of 20

Monica Seles posed the biggest challenge to Graf's throne. Seles was already a World No. 1 and had won eight singles Majors before she turned 20. In 1991, she won the Australian Open, French Open and US Open by defeating Jana Novotna, Arantxa Sanchez Vicario and Martina Navratilova in the finals. Seles did not play at Wimbledon due to a shin injury.

The following year, Seles made the final of every Slam. She defeated Mary Joe Fernández, Graf and Vicario at the Australian Open, French Open and US Open finals. The former World No. 1's only defeat at the Majors in 1992 came against Graf at Wimbledon.

#6 Martina Hingis

Martina Hingis won her first Slam at the age of 16

Martina Hingis won her first ever singles Major at the Australian Open in 1997. She was only 16 years old at the time. In the same season, after becoming the youngest World No. 1, Hingis finished as the runner-up to Iva Majoli at Roland Garros.

The Swiss Miss would make yet another run to the final at Wimbledon, where she defeated Novotna to become the youngest Wimbledon champion in the Open Era. At the US Open, she did not drop a set in the entire tournament and defeated Venus Williams in the final. Hingis won 75 of the 80 matches she played that season.

#7 Serena Williams

Serena Williams

Serena Williams has won three Majors in a single season twice in her illustrious career. In 2002, she missed the Australian Open due to an ankle injury. Between the 2002 French Open and the 2003 Australian Open, Serena faced her older sister Venus Williams in the final of all the Majors. Each time, it was Serena who triumphed.

Thirteen years later, Williams, then a winner of 18 singles Slams, began the 2015 season as World No. 1. She defeated Maria Sharapova, Lucie Safarova and Garbine Muguruza in the finals of the Australian Open, French Open and Wimbledon respectively. At the US Open, aiming for a calendar Slam, Williams made the semis after defeating her sister in the quarterfinals. In the semis, Williams was upset by Italy's Roberta Vinci, who joined compatriot and eventual champion Flavia Pennetta in the final.