PARIS, Feb 2 — Serena Williams has bolstered her position atop the WTA world rankings after winning the Australian Open on Saturday.

The 33-year-old American defeated Maria Sharapova in straight sets for her sixth Grand Slam title in Melbourne and 19th in all.

Williams is over 1,500 points clear of the Russian who in turn is well ahead of third placed Simona Halep of Romania.

One of the biggest movers of the week was Serena’s older sister Venus. The former world number one reached the last eight in Melbourne for her first Grand Slam quarter-final since 2010.

That hoisted her seven places in the rankings up to just outside the top 10 at 11th.

Surprise Melbourne semi-finalist Madison Keys gained 15 places to break into the top 20 for the first time in her career.

WTA top 20 world rankings:

1. Serena Williams (USA)             9,776

2. Maria Sharapova (RUS)             8,210

3. Simona Halep (ROM)                6,571

4. Petra Kvitova (CZE)               6,480

5. Caroline Wozniacki (DEN)          4,565 (+3)

6. Ana Ivanovic (SRB)                4,425 (-1)

7. Eugénie Bouchard (CAN)            4,365

8. Agnieszka Radwanska (POL)         4,270 (-2)

9. Ekaterina Makarova (RUS)          3,285 (+2)

10. Angelique Kerber (GER)           3,130 (-1)

11. Venus Williams (USA)             2,790 (+7)

12. Andrea Petkovic (GER)            2,735 (+1)

13. Sara Errani (ITA)                2,551 (+1)

14. Flavia Pennetta (ITA)            2,441 (-2)

15. Lucie Safarova (CZE)             2,425 (+1)

16. Jelena Jankovic (SER)            2,360 (-1)

17. Carla Suarez Navarro (ESP)       2,295

18. Dominika Cibulkova (SLQ)         2,137 (-8)

19. Alizé Cornet (FRA)               2,125

20. Madison Keys (USA)               2,100 (+15) — AFP