About two years ago, Srdan Djokovic, like any other father, sat down with his 18-year-old son to discuss his future.
"My dad asked me if I wanted to really play tennis, and that if the answer was 'yes', then it would have to be tennis all the way," said Marko, the second of Srdan's three sons.
And Marko's reply was obvious. Elder brother Novak was still not the world No 1, but he was among men's tennis elite, winner of the 2008 Australian Open and mentioned in the same breath as Roger Federer and Rafael Nadal.
Four years younger than Novak, had grown up idolising his elder brother from an early age and when the time came to pick his career, he decided to follow his footsteps. Had he chosen otherwise, Marko "would have gone to university and then become a business man".
"I remember when he was six years old, he started playing tennis on the mountain. I was following him all these years, going to school as well, watching him, practising next to him. He was my idol from when I was younger.
"So I was always in tennis, and my younger brother as well. We like it a lot and it was my decision, nobody else's.
"My father told me: 'You can chose whatever you want to do in your life. It's your life.' I chose tennis."
That Marko has grown up idolising Novak is obvious when you see him on court. His movement on the baseline, the stretched forehand and that cap, they all remind you of the elder brother's influence.
Of course, he does not bounce the ball as many times as Novak, but Andrey Golubev could not help but notice the similarities.
"They have pretty similar technique, that's what I could see," said Golubev, who played Marko in the opening match of the Dubai Duty Free ATP Chammpionships yesterday. "I'm playing, not watching his game, but, yeah, of course similar technique. I think he's moving pretty well."
Novak was courtside for the match, but that did not help Marko much. Starting the game with a break, the Serbian fell apart and was beaten 6-3, 6-2 in 71 minutes.
The result was expected as Marko is ranked a modest No 869 in the world and has lost the two earlier matches he has played on the ATP main tour.
A wrist injury has also not helped his cause and, after undergoing surgery, Marko has been trying to climb up the ranking charts through the challenger tour.
Having the world No 1 as his brother helped Marko get a wildcard in Dubai and Novak thanked the organisers for that.
"He has been struggling with injuries for the last couple of years and has been missing consistency in his career," said Novak, who cruised past Cedrik-Marcel Stebe 6-4, 6-2 last night.
"He had a surgery that took him off the circuit for 10 months last year and now he is back and trying to raise his level of confidence."
Marko remembers the frustrating time he spent out with injury, but is gradually rediscovering his confidence.
"I had a really tough time because I'm still young and I was thinking to go to college or not," he said. But now I know that I can play good tennis. Golubev played really good today, and I saw the quality of the tennis is not that far away from my tennis. Hopefully I can improve a lot. I'm still young, so will be good to continue."
The youngest of the Djokovic siblings is also playing tennis and a lot of good things are being said about him. Djordje, 16, has trained at Nick Bollettieri Academy in Florida and Radek Stepanek, an ATP professional, told Novak that "he's a copy-paste of my forehand".
"My younger brother is doing well," said Novak. "He is playing a lot of junior events. He is 16 years old and they are both trying to find their way through their tennis careers.
"On the one hand, it's good they have a brother who is established at the top of men's tennis and he can give them right advices at the right time, give them opportunities that they might not get individually themselves.
"On the other hand, there is a lot of pressure they have been carrying for the last five years. They are quiet and still have not matured, especially the younger one, to handle that kind of pressure.
"But look, they both have different ways from what I had and hopefully they can make it through."