Switzerland's Roger Federer is the world's highest paid tennis player even though he has slipped to No. 7 in the ATP rankings, while Spain's Rafael Nadal is No. 4 on a new list published by Forbes magazine.

The list, which takes into account tennis players' earnings between June 2012 and June 2013, was published to coincide with the start of the U.S. Open, the year's last Grand Slam event, which is taking place in New York.

The 32-year-old Federer, who many consider the best tennis player of all time, earned $71.5 million during the 12-month period, thanks to a December 2012 tour of South America that netted him $14 million for playing six matches.

"Federer has the most impressive endorsement portfolio in sports, with ten sponsors that collectively pay him more than $40 million annually, including long-term deals with Nike, Rolex, Wilson and Credit Suisse. The newest addition is champagne brand Moet & Chandon, which signed Federer to a five-year deal at the end of 2012," Forbes said.

Russia's Maria Sharapova is in the No. 2 spot on the list, with $29 million in earnings, Forbes said.

"Sharapova completed the career Grand Slam when she won the 2012 French Open. The win triggered lucrative bonuses with sponsors Nike and Head. She launched her own candy line, Sugarpova, last year and plans to sell accessories under the brand starting this fall," Forbes said.

Serbia's Novak Djokovic, the world No. 1, is in third place on the list, pulling in $26.9 million, with about half of that sum coming from prize money.

The 26-year-old Djokovic has reached the finals of nine of the last 12 Grand Slams.

"Most top players have a apparel/shoe deal with one brand, but Djokovic added Adidas as a sponsor in April to go with his clothing sponsor Uniqlo," Forbes said.

The 27-year-old Nadal, for his part, earned $26.4 million despite sustaining a knee injury that kept him off the ATP Tour for seven months.

The Spaniard has been unstoppable since returning to action in February, playing in 11 finals, winning nine titles and earning $6.8 million in prize money.

"He left IMG in December to start his own management company with his father and manager. Major sponsors include Nike, Babolat, Kia Motors and Bacardi," Forbes said. EFE