Andy Murray vs Ivo Karlovic: Croatian ace Karlovic explains the highs and lows of being 6ft 11

Big-serving Croatian, who is next up for British No 1 at the French Open, speaks to Paul Newman in Paris

Ivo Karlovic, 37, is the oldest man to reach the third round of a Slam since Jimmy Connors back in 1991 (Getty)

Being 6ft 11in tall and weighing more than 16 stone has its advantages for Ivo Karlovic, who uses his massive frame to deliver one of the most powerful serves in the game. In his younger days on the tour, however, particularly when money was tight, it was not always easy being the biggest man in professional tennis.

Karlovic, who takes on Andy Murray in the third round of the French Open here on Friday, used to fly economy class everywhere, even on long-haul trips. “I remember once when I flew to Australia in the middle seat,” he recalls. “Nobody wanted to switch because it was a long flight. I remember when I got out of the airplane my knees were hurting for the next week. It was ridiculous.

“Now I only fly economy if it’s a short flight in Europe. If it’s a bit longer, there’s no way that I would do it.”

At home Karlovic has a customised bed, while all his trousers are specially made for him. For years his biggest problem was finding size 17 tennis shoes, though his kit sponsor now provides them. “I could get basketball shoes and normal running shoes, but not tennis shoes,” he says. “I would have to wear tennis shoes that were two sizes too small. They destroyed my feet. That’s why after every season my nails would be completely dead.”

Even in an era when more players are competing into their thirties – there were a record 51 thirty-somethings among the 128 starters for the men’s singles here – Karlovic is an exception. At 37 the Croatian will be the oldest player to appear in the third round of a Grand Slam tournament since Jimmy Connors played in the 1991 US Open at the age of 38.

“I reached the top 100 when I was 24, which is a bit later than other guys, so I don’t feel that I am used up,” Karlovic says. “I also think that nowadays it’s a bit different. Everybody is doing a lot more work in the gym, taking care of their body, and that’s why everybody’s peak is a little bit later than it used to be in the 70s or the 80s.”

Karlovic believes that for older players motivation can be a bigger problem than fitness. “When you are young everything is new and you are always eager to win and go on,” he says. “When you are a little bit older, every day you need to find something that makes you happy, to be able to continue doing this.”

He adds: “Airplanes and the travelling is the worst bit for me, but I just keep reminding myself that this is an unbelievable life and that I really like what I am doing. I just have to squeeze as much out of it as I can.”

Now that he can afford flight upgrades, the worst part of travelling for Karlovic is leaving behind Alsi, his wife, and their four-year-old daughter, Jada Valentina. “When I leave my home to go to the airport it’s always really difficult, almost heart-breaking,” Karlovic says. “My daughter says to me: ‘You don’t have to go, Daddy! You can stay!’ I try to explain to her that I will go and earn enough money to buy her a doll. Then she says: ‘OK, Daddy, go'!”

Karlovic, who has homes in Florida and Dubai, brings back a present from most trips and also talks to his daughter on Skype while he is away. “We talk for a bit almost every day,” he says. “We play over the screen with dolls and stuff.”

The idea of Karlovic playing with dolls in front of a computer screen is quite a contrast to the sight of the Croatian man mountain on court, pummelling his opponents with his cannonball serves. Last year he broke the all-time career record of 10,237 aces held by Goran Ivanisevic, who was one of the first to congratulate his fellow countryman.

“When I was young he was my hero,” Karlovic says. “I think the only time in my life that I got star-struck was when I met him when I was about 15. To take the record from one of the greatest servers ever was just unbelievable.”

Karlovic always remembers being taller than those around him, even when he was at nursery school, and has always had a big serve. “When I was young I used to practise it a lot,” he says. “Firstly it was because I liked to serve. I grew up watching players like Goran Ivanisevic and Boris Becker and they hit unbelievable serves.

I could get basketball shoes and normal running shoes. I would have to wear tennis shoes that were two sizes too small. They destroyed my feet

&#13; <p>Ivo Karlovic on his wardrobe issues</p>&#13;

“The other reason was because I didn’t have anybody to hit with when I was 14 or 15. I would have to wait until the evening. All the courts were empty, so I would practise my serve a lot during the day.”

Karlovic thinks the effectiveness of his serve comes from a combination of power, placement and variation. “There is also a little bit of a trick because there are guys who try to read it and guess a bit, so you have to know how to fool them, so they will believe that one thing will happen but then something else actually does. It’s all a bit of a game.”

He adds: “When my serve is on I feel that nobody can return it. When my serve is broken it’s usually because I break myself.”

Ivo Karlovic has a booming serve (Getty)

Karlovic made his tour debut in 2001 in the week of the 9/11 attacks in New York, but the first time he drew major attention came two years later. Ranked No 203 in the world and playing his very first match at Wimbledon, Karlovic beat Lleyton Hewitt in four sets. It is only the second time in All England Club history that the defending men’s champion has gone out in the first round.

Had he believed at the time that he could beat Hewitt? “No!” Karlovic laughs. “I knew that I had to believe that it could happen, but nobody really believed that I could. I remember during the first set I was looking around thinking: ‘What is this huge court?’ I was losing easily. I don’t know what happened afterwards. There was maybe a little switch in my head. I was repeating to myself: ‘You can do it. You can do it.’ That was even though I didn’t really think I was going to be able to.”