Bulgaria's best female tennis player, Tsvetana Pironkova, has climbed the rankings to a new career-high of No 31 in the world on the back of her success at the US Open, where she bowed out in the second round.

The performance of the Bulgarian, who turned 23 on Monday and has recently transformed from a huge underdog into a surprise sensation after her success at Wimbledon, helped her jump up by three spots in the ranking with 1803 points total.

On September 1 Pironkova dropped out in the second round in the singles competition of the US Open Grand Slam championship against 24-year-old Mandy Minella from Luxembourg (4:6, 0:6) and received USD 31 000.

Pironkova's surprise run to the Wimbledon semi-finals pushed her WTA Tour ranking to 34th in the world.

Five-time champion Venus Williams suffered a shocking 6-2, 6-3 defeat against Pironkova in the quarter-finals at Wimbledon at the end of June .

This was the second time in three matches that the 22-year-old has defeated Williams, who also lost to her in the first round at the 2006 Australian Open. Pironkova had never moved past the second round in 18 previous Grand Slam appearances and became the first ever Bulgarian player to reach the Wimbledon semi-finals.

Her best ranking before Wimbledon was No.40 in June, 2008.

WTA leader continues to be American Serena Williams with 6995 points, followed by Denmark's Caroline Wozniacki with 5910 points while Serena's sister Venus is third with 5796 points.