Anna Kournikova

Thirteen-time Grand Slam singles champion and former world No.1 Serena Williams has been named the US's most popular female athlete by Harris Interactive for the third straight year.

If you've been watching the French Open 2011 at all, it's easy to see that tennis is an incredible sport. A mix of mental agility and physical coordination, skill and fitness, it's also a crazy-good workout. While there are a number of female tennis players who inspire us to new levels of fitness on and off the court, here are the top five we admire.

5 Female Tennis Stars We Admire

Russian trailblazer Anna Kournikova's post-WTA career has taken another interesting turn - in the direction of Hollywood - with the news the former doubles world No.1 will be the new celebrity trainer on hit American reality TV show The Biggest Loser.

An excited Kournikova - who celebrates her 30th birthday on June 7 - was on hand when her appointment was confirmed during the Tuesday night finale of the weight loss and well-being show, which is being overhauled ahead of its twelfth season.

Slovak tennis fans were given a pre-Christmas treat this week when national tennis heroes Dominika Cibulkova and Dominik Hrbaty hosted visiting greats Thomas Muster and Anna Kournikova for a charity exhibition at Bratislava's Sibamac Arena.

The Spice Girls of tennis, Martina Hingis and Anna Kournikova, made a popular return to the All-England Club on Tuesday for the Invitational Doubles, beating Sam Smith and Anne Hobbs, 62 64.

The renowned "Dream Team" of women's tennis is back. Martina Hingis and Anna Kournikova confirmed Tuesday they will compete together in the Ladies' Invitation Doubles at Wimbledon this June. The pair formed one of the most formidable doubles tandems in women's tennis in the 1990s, winning two Grand Slams, reaching No.1 in doubles and earning 1999 Doubles Team of the Year from the Sony Ericsson WTA Tour. "I'm so excited to be returning to the UK to play doubles with Martina again," Kournikova said regarding the announcement.

There have been so many Wimbledon heartthrobs and honeys over the years, but American hunk Andre Agassi and Russian beauty Anna Kournikova have been voted the sexiest tennis players of all time.

To celebrate the 75th year of their association with Wimbledon, Robinsons asked 5,000 British fans who has caught the eye the most over the years.

The survey found that rough and rugged Agassi came out top with over a third of women (37 per cent), while Kournikova was a firm favourite and top choice with 32 per cent of men voting for the leggy blonde.

Maria Sharapova has been voted the sexiest female tennis player on the circuit.

The gorgeous Russian scored 58 per cent to beat the likes of Ana Ivanovic, Elena Dementieva and Daniela Hantuchova to come top in a new poll from Robinsons.

And Spanish sensation Rafa Nadal — who claimed 55 per cent — was the man most women wanted to play a love game with after fending off strong competition from Britain's Andy Murray.