Madison Keys (USA)

Age: 21

World Ranking: 8

Seems to have been around for ages, but still only 21, and now back working with Lindsay Davenport. May be a bit much for her to make good on the promise of filling the Serena Williams-size hole at the summit of the sport when she finally retires but has huge potential assuming she shows no ill effects from the wrist surgery late last year which sees her miss the Australian Open.

Monica Puig (Puerto Rico)

Age: 23

World Ranking: 32

Older than many of the others on this list, the powerful Puig had won just one major tournament and was unseeded when she outgunned the rest of the field to take the Olympic singles title in Rio. This was Puerto Rico's first ever Olympic gold in any sport and this could be a big year for her if she can continue to put everything together.

Catherine Bellis (USA)

Age: 17

World Ranking: 74

Another who misses the Australian Open, with a hamstring strain, Bellis won the USTA Under-18 girls competition at the age of 15, making her the youngest winner since Lindsay Davenport, and she doesn't show much signs of slowing down. She took her first WTA title in Honolulu at the end of last year and is the youngest player in the top 100.

Ana Konjuh (Croatia)

Age: 19

World Ranking: 36

Just turned 19, but still comfortably accommodated within the world's top 50 players, the Croatian reached the WTA final in Auckland last year, where she went down to another fast-rising star in the form of Lauren Davis of the USA. Won Australian Open junior title in 2013, and rewarded herself with a tattoo on her wrist which says 'faith'.

Belinda Bencic (Switzerland)

Age: 19

World Ranking: 48

Coached by Melanie Molitor - Martina Hingis' mum - teenager Bencic was ranked in the world's top 10 players only 12 months ago. Has two WTA tournament wins on her resume, and four other finals, and has the world at her feet if she can stay injury free. Recently spotted playing alongside Roger Federer at the Hopman Cup but faces Serena Williams in the first round in Melbourne.