The world's most devastating serve

Ivo Karlović of Croatia has arguably the most devastating serve in the tennis circuit today.

He has the second fastest first serve (at 153 miles per hour, after Andy Roddick's 155 m/h delivery) and the fastest second serve (at 144 m/h) on record, has served the second all-time number of aces in a season(1,318 aces, behind Goran Ivanišević's 1,477 in 1996) , and his record of serving the most number of aces (78) in a match was only broken by John Isner and Nicholas Mahut in the longest match in tennis history in Wimbledon last year.

Despite having such a fearsome serve, Karlović's rise to tennis promince has been anything but easy. "I made my career almost out of nothing," he said. "Nobody in the Top 100 has had such a difficult path."

His early ambition was to become a basketball player, but it was quickly extinguished when "aged 13, the coach put me in a team of children five years older than me".

He then began to focus on tennis, but it was, as he said, "a difficult path". Remembering his childhood in Salata, he said: "I had no place to practise and nobody to practise with. I would therefore wait until the courts had cleared and begin practising my serve again and again. The ritual would sometimes go on long into the night."

Nobody had ever predicted a future Karlović except his family. "My parents were always giving me support," he said. "Even though they didn't travel with me because there wasn't the money to do so. They believed in me no matter what. I had unbelievable support."

The early days in his tennis career was tough. For years, he was travelling alone and had to worry about where his next pay cheque would come from or when it would come, and sometimes the money dried up for him. "I had to play league tennis in Germany, Austria and France," Karlović recalled. "It went on for months, trying to get money to survive, while other aspiring professionals played on the tour."

He almost backed away in 2003. "The 2003 season was definitely the toughest of my career," said Karlovic. "I just lost in the first round of a small tournament at Melun in France and began to wonder: Is it worth it? That was the only thing going through my mind. I really questioned whether I could make it, whether it was worth travelling to even the smallest of events."

Fortunately for Karlović and maybe the tennis world, he did not quit after the tough loss, for, ironically, in was in that same year that his career made a breakthrough. Having qualified for Wimbledon, Karlović drew the top seed and defending champion Lleyton Hewitt in the first round. Who would have thought that he would win that match by three sets to one and make Hewitt become the first defending men's singles champion to lose in the first round since 1967? After that confidence boosting victory, Karlović's career took off and there has been no looking back.

Karlović has had a fairly successful tennis career so far, having won four ATP tournaments and reached no.14 in world ranking in 2008. But he is remarkably down-to-earth. "I have never been jealous about other players who have money and sponsors," he said. "It would have been nice to have had that support starting out, but I did it my way: the hard way. Even today, I would never have changed anything in my career. Everything that has happened, happened for a reason."

That humble statement was as well delivered as any of his powerful aces.