World No.1 Naomi Osaka's meteoric rise to the top of the rankings has been a historic one. The 21-year-old from Japan snapped Simona Halep's 48-week reign at No.1 by defeating No.2 Petra Kvitova to win her second consecutive major title at the Australian Open in January. With the feat, Osaka became the first Asian player, let alone Japanese player, man or woman, to hold the World No.1 ranking.

Osaka is now the reigning champion of three of the six biggest hardcourt events of the last 12 months. Along with her Melbourne victory, Osaka won her first WTA title at the 2018 BNP Paribas Open last March, and her first Slam title six months later at the US Open. 

Osaka's rise through the rankings went from gradual to exponential, all in the span of 13 months. Before the 2018 Australian Open, Osaka was ranked No.72 and she entered Indian Wells ranked No.44. That dominant title run, which saw her drop just one set while scoring wins over then-No.1 Halep, Karolina Pliskova, Maria Sharapova, Agnieszka Radwanska, and Daria Kasatkina, boosted her to a career-high No.22. 

After hovering around the Top 20 through a disappointing clay and grass season, Osaka made her Top 10 debut last fall on September 10, 2018 after winning the US Open. Just 20 weeks later she became the 26th woman to hold the WTA World No.1 ranking on January 28, 2019, the fastest rise to No.1 for any player since the advent of computerized rankings*.

Osaka's 20 weeks bests the 25-week mark previously set by both Martina Hingis and Evonne Goolagong Cawley. 

Chris Evert (USA)
Top 10 Debut: November 3, 1975 (20 years old)
No.1 Debut: November 3, 1975 (20 years old)

*Evert was the first WTA World No.1 when the computerized rankings debuted on November 3, 1975.

Naomi Osaka (JPN)
Top 10 Debut: September 10, 2018 (20 years old)
No.1 Debut: January 28, 2019 (21 years old)

Martina Hingis (SUI)
Top 10 Debut: October 7, 1996 (16 years old)
No.1 Debut: March 31, 1997 (16 years old)

Evonne Goolagong Cawley (AUS)
Top 10 Debut: November 3, 1975 (24 years old)
No.1 Debut: April 26, 1976 (24 years old)

Ana Ivanovic became the first woman representing Serbia to hold the No.1 ranking after winning 2008 Roland Garros. (Getty Images)

Ana Ivanovic (SRB)
Top 10 Debut: May 14, 2007 (19 years old)
No.1 Debut: June 9, 2008 (20 years old)

Maria Sharapova (RUS)
Top 10 Debut: July 5, 2004 (17 years old)
No.1 Debut: August 22, 2005 (18 years old)

Caroline Wozniacki (DEN)
Top 10 Debut: May 18, 2009 (18 years old)
No.1 Debut: October 11, 2010 (20 years old)

Monica Seles (USA)
Top 10 Debut: September 11, 1989 (15 years old)
No.1 Debut: March 11, 1991 (17 years old)

Jelena Jankovic (SRB)
Top 10 Debut: January 29, 2007 (21 years old)
No.1 Debut: August 11, 2008 (23 years old)

Karolina Pliskova (CZE)
Top 10 Debut: August 10, 2015 (23 years old)
No.1 Debut: July 17, 2017 (25 years old)

Stefanie Graf won her first of 22 major titles at the 1987 French Open and made her No.1 debut three months later. (Getty Images)

Stefanie Graf (GER)
Top 10 Debut: August 5, 1985 (16 years old)
No.1 Debut: August 17, 1987 (18 years old)

Tracy Austin (USA)
Top 10 Debut: March 13, 1978 (15 years old)
No.1 Debut: April 7, 1980 (17 years old)

Garbiñe Muguruza (ESP)
Top 10 Debut: July 13, 2015 (21 years old)
No.1 Debut: September 11, 2017 (23 years old)

Kim Clijsters (BEL)
Top 10 Debut: June 11, 2001 (18 years old)
No.1 Debut: August 11, 2003 (20 years old)

Kim Clijsters and Justine Henin both debuted at No.1 in 2003, facing off in two major finals that season. (Getty)

Justine Henin (BEL)
Top 10 Debut: June 11, 2001 (19 years old)
No.1 Debut: October 20, 2003 (21 years old)

Dinara Safina (RUS)
Top 10 Debut: October 2, 2006 (20 years old)
No.1 Debut: April 20, 2009 (22 years old)

Martina Navratilova (USA)
Top 10 Debut: November 3, 1975 (19 years old)
No.1 Debut: July 10, 1978 (21 years old)

Victoria Azarenka (BLR)
Top 10 Debut: March 23, 2009 (19 years old)
No.1 Debut: January 30, 2012 (22 years old)

Five months after Venus Williams made her No.1 debut in February 2002, younger sister Serena rose to No.1 in July after winning Wimbledon. (Getty)

Serena Williams (USA)
Top 10 Debut: April 5, 1999 (17 years old)
No.1 Debut: July 8, 2002 (20 years old)

Simona Halep (ROU)
Top 10 Debut: January 27, 2014 (22 years old)
No.1 Debut: October 9, 2017 (26 years old)

Venus Williams (USA)
Top 10 Debut: March 30, 1998 (17 years old)
No.1 Debut: February 25, 2002 (21 years old)

Angelique Kerber (GER)
Top 10 Debut: May 21, 2012 (24 years old)
No.1 Debut: September 12, 2016 (28 years old)

Lindsay Davenport won her first major at the 1998 US Open and finished the season as WTA Year-End No.1. (Getty)

Lindsay Davenport (USA)
Top 10 Debut: May 9, 1994 (17 years old)
No.1 Debut: October 12, 1998 (22 years old)

Amelie Mauresmo (FRA)
Top 10 Debut: May 10, 1999 (19 years old)
No.1 Debut: September 13, 2004 (25 years old)

Arantxa Sanchez-Vicario (ESP)
Top 10 Debut: May 22, 1989 (17 years old)
No.1 Debut: February 6, 1995 (23 years old)

Jennifer Capriati (USA)
Top 10 Debut: October 29, 1990 (14 years old)
No.1 Debut: October 15, 2001 (25 years old)