I feel bad for Marko, tennis is not his calling. But how many sports great has equally talented siblings? not many that I can recall. At least he has the good look
Tennis has definitely had some families doing well.
DJOKOVIC CLAN KEEP IT IN THE FAMILY
Marko Djokovic failed to win his first main draw ATP Tour match in the Serbia Open in Belgrade this week, leaving the youngster with a long way to go to emulate the feats of his older brother Novak.
With another Djokovic brother, Djordje, still to start on the tour, the chances are Serbia's foremost tennis family could be dominating the game for some time to come. But it does not always follow that talent will run in the family.
Patrick McEnroe was no slouch as a professional, but his playing career pales into insignificance when put alongside his older brother John, who claimed seven Grand Slam titles in his illustrious career.
Patrick McEnroe won 16 career titles and reached the semi-final of the 1991 Australian Open, where he lost to Boris Becker. Like brother John, he would go on to captain the US Davis Cup team.
The Sanchez brothers, Emilio and Javier, made history by becoming the first brothers to contest a tour final in the Open era when they squared off in Madrid in 1987. Their sister, Arantxa Sanchez-Vicario, was no slouch either.
While Andy Murray rose up the singles rankings, his older brother Jamie quickly opted to concentrate entirely on doubles - with some reward, as he beat Andy to a Grand Slam title when he won the Wimbledon mixed doubles in 2007 with Jelena Jankovic.
Neither of the Bryan brothers, Bob and Mike, fancied a singles career, instead forging a partnership which has made them the longest-reigning doubles world number ones with 77 titles - including 11 Grand Slams - to their name.
Tennis success is a family affair in Ecuador, where Nicolas Lapentti - nephew of former French Open champion Andres Gomez - was a long-time fixture in the world's top 50 and reached the last eight of both French and Australian Opens.
While younger brother Giovanni never scaled such heights, the teenager retains a famous place in Davis Cup history as the man who dispatched Arvind Parmar to give Ecuador a stunning win over Great Britain at Wimbledon in 2000.
The diminutive Belgian Rochus brothers, Christophe and Olivier, were a fixture on the circuit for some years until Christophe retired at the end of the 2009 season. Olivier still plays.
The Lloyd brothers John and David brought success to Great Britain but were hard-pushed to emulate the Renshaw twins William and Ernest. William won seven Wimbledon world titles while Ernest had to make do with one.
Sibling rivalry is also prevalent in the women's game, led obviously by the Williams sisters but also including Polish pair Agnieszka and Urszula Radwanska, and the respective trios of Bondarenko and Maleeva sisters.