Sharapova makes a fortune off the court but did reach the Wimbledon final  in 2011 [GALLO/GETTY] 

Maria Sharapova may not have won a grand slam title since 2008, but the Russian tennis player remains unchallenged as the world's highest paid woman in professional sports.

For the seventh straight year, Sharapova topped the annual list provided by Forbes magazine, despite failing to add to her three grand slam titles, although she did make the Wimbledon final in July.

Sharapova's earnings, mostly off-court endorsements, were estimated at $25 million, twice as much as her nearest rival.

Her profile extends far beyond tennis, and she has been featured in a number of modeling assignments, including a feature in Sports Illustrated Swimsuit Issue.

The Russian has featured in advertisements for Nike, Prince and Canon and is one of the most searched for athletes on the internet.

The second biggest earner was Denmark's Caroline Wozniacki, the current women's world number one.

American racing driver Danica Patrick was third with $12 million followed by tennis players Venus Williams, Belgium's Kim Clijsters and Serena Williams.

Seven of the top nine female earners were tennis players, including China's Li Na, who made $8 million last year but was expected to soar up the rankings and challenge Sharapova for the top spot after her breakthrough win at the French Open.

Top 10 women earners

1. Maria Sharapova $25 million (Russia, tennis)
2. Caroline Wozniacki $12.5 million (Denmark, tennis)
3. Danica Patrick $12 million (U.S., motor racing)
4. Venus Williams $11.5 million (U.S., tennis)
5. Kim Clijsters $11 million (Belgium, tennis)
6. Serena Williams $10.5 million (U.S., tennis)
7. Kim Yuna $10 million (figure skating, South Korea)
8. Li Na $8 million (China, tennis)
9. Ana Ivanovic $6 million (Serbia, tennis)
10. Paula Creamer $5.5 million (U.S., golf)

Source: Reuters