If he can keep his focus there’s no doubting Kyrgios can win a grand slam,  but at the moment that’s proving a big if and he is not yet fulfilling his potential. That said he’s in the world’s top 20 and is by far the most entertaining character on the tour right now.

Career highlight: A stunning four-set win against the then World No 1 Nadal in the fourth round of Wimbledon two years ago.

Dominic Thiem

Nationality: Austria

Age: 22

World Ranking: 8

Thiem has been touted as a future major winner for some time now, but it wasn’t until this year that he started to show just how good he can be. Since the start of 2016, Thiem has won four titles, reached his first grand slam semi-final at the French Open, and climbed into the world’s top 10.

Thiem has an excellent baseline game and his stand-out single-handed backhand, which has shades of Roger Federer, could propel him to the very top of the sport.

Career highlight: Reaching the French Open semi-final earlier this month.

Alexander Zverev

Nationality: Germany

Age: 19

World Ranking: 28

Tennis’s highest-ranked teenager and the youngest player in the world’s top 30 since a certain Novak Djokovic ten years ago. Zverev has the talent and technique to reach the very top, so the focus now is on building his fitness – with the help of Andy Murray’s former physical trainer Jez Green – and strengthening his mental resolve in tight situations.

On the latter, Zverev seems to be improving – he was able to get through an extremely tight match against Roger Federer in Halle last week, which contrasted with a nightmare defeat against Rafa Nadal in Indian Wells having botched an easy volley at match point. After that match, Nadal called Zverev “a future No 1”, and the future does look extremely bright for the man known as ‘Sascha’.

Career highlight: Defeating Federer on grass in the Halle semi-final last week.

Borna Coric

Nationality: Croatia

Age: 19

World Ranking: 49

The hugely talented Croatian served notice of his potential with victories over Rafael Nadal and Andy Murray in his first couple of years on the tour. Coric has since reached two ATP finals and recorded a number of impressive Davis Cup wins, including the decisive rubber against Belgium earlier this year.  Still only 19, Coric is coached by Andy Murray’s former coach Miles Maclagan.

Career highlight: Beating Rafael Nadal in straight sets at the Swiss Open in 2014, aged 17.

Bernard Tomic

Nationality: Australia

Age: 23

World Ranking: 19

Like his compatriot Kyrgios, the biggest obstacle to Tomic becoming a top-10 player appears to be himself. There’s no doubting the Aussie’s ability, but his career has been littered with misdemenaours, both on and off the court. Most recently Tomic was accused of giving up in a match against Fabio Fognini in March, and it is antics like these that have earned him the nickname ‘Tomic the Tank Engine’.

On grass in particular though Tomic can be a real handful – he reached the Wimbledon quarter-final in 2011 and last week at Queen’s looked in good shape until a semi-final defeat by Milos Raonic. Tomic insists he is misunderstood and that people mistake his languid style for lack of effort, but only by winning more consistently will he convince the critics that they are wide of the mark.

Career highlight: Becoming the youngest player since Boris Becker  to reach the Wimbledon quarter-final, aged 18

Belinda Bencic

Nationality: Switzerland

Age: 19

World Ranking: 8

Lucky enough to have five-time grand slam champion Martina Hingis as her mentor, and blessed with a similarly feather-light touch and varied game. Bencic is not one of the game’s biggest hitters, but has excellent court awareness and soft hands and has beaten almost all of the game’s leading lights.

In fact she beat many of them in the space of a week during an extraordinary run at the Rogers Cup last year where she defeated Caroline Wozniacki, Sabine Lisicki, Simona Halep, Eugenie Bouchard, Ana Ivanovic and Serena Williams en route to the title. Bencic has continued that form this year and broke into the world’s top 10 in February, aged just 18.

Career highlight: The magnificent Rogers Cup win

Madison Keys

Nationality: USA

Age: 21

World Ranking: 10

With a big serve and monster forehand, Keys has the tools to become a real threat – especially on grass. It was on that surface that Keys won her first title – at Eastbourne two years ago – and last week she won the Aegon Classic in Birmingham to claim a place in the world’s top 10. At grand slam level, Keys reached the Wimbledon quarter-final and Australian Open semi-final last year, and has a real shot at going deep at SW19 this time around.

Career highlight: Breaking into world’s top 10 this week

Sloane Stephens

Nationality: USA

Age: 23

World Ranking: 20

When Stephens defeated Serena Williams as a teenager at the 2013 Australian Open en route to the semi-final, it appeared only a matter of time before she started to challenge for grand slams.

As yet though the talented American has not quite made the next step up, and her best performance at a slam remains that run to the semis in Melbourne three years ago. But after winning three titles this year and still aged just 23, we shouldn’t rule out Stephens getting her hands on a slam title one day.

Career highlight: Defeating Serena Williams at the at the 2013 Australian Open, aged 19

Elina Svitolina

Nationality: Ukraine

Age: 21

World Ranking: 19

Coached by multiple grand slam champion Justine Henin, Svitolina has made great strides over the last year or so, and got as high as 14 in the world in March. The Ukrainian is the youngest player in the top 20 after Keys, and has won a title in each of the last four years, as well as reaching the French Open quarter-final last year. A fourth-round appearance at Roland Garros in May, where she won the title as a junior, underlines Svitolina’s consistency, and has given her a platform to challenge at the remaining majors this year.

Career highlight: The run to the last eight at the French Open last year

Daria Kasatkina

Nationality: Russia

Age: 19

World Ranking: 31

A former French Open junior champion, Kasatkina has shot up the rankings this year from 72 at the end of 2015 to a current high of 31.

Not a natural on grass but Kasatkina has reached the third round of the other three slams since she last played at Wimbledon and looks like one for the future.

Career highlight: Beating Venus Williams in Auckland earlier this year

Article written by: Charlie Eccleshare of The Telegraph