Former world number seven Mario Ancic has retired at the age of 26 to become a lawyer after years battling illness and injury.
The big-serving Croatian, who earned the nickname "Super Mario" after reaching the Wimbledon semi-finals in 2004, achieved his career-high ranking in 2006 but has struggled since with the debilitating illness mononucleosis as well as back and knee problems.
"I can't stand it any more, I have finished my career," Ancic was quoted as saying by Croatian daily Jutarnji List on Monday.
"I'm forced to quit because nature has decided it's time. My back can't withstand the effort of professional tennis," he added.
Ancic, whose greatest moment came in 2005 when he won the deciding rubber in the Davis Cup final against Slovakia, is due to hold a news conference on Wednesday.
Ivan Ljubicic, who Ancic partnered in 2004 to the Olympic bronze medal in doubles, expressed his sympathy for his compatriot.
"It's terrible. I mean, that's the worst way for a sportsman to finish the career," Ljubicic told reporters after being forced to quit in his first-round match in Dubai with an injury.
"Fortunately he has a law degree. He's already practising that. His life, it will go on.
"Together we achieved so much at such early stages of our careers. It was just incredibly unfortunate to kind of finish it that way.
"I saw him in Zagreb just a couple of weeks ago. We are in touch all the time. I didn't bother asking him too much how he was, because I knew the answer. It was not good, not good for the last three years," he added.
During his lengthy spells out of tennis, Ancic, whose father owns a supermarket chain in Croatia, studied for a degree in law at the University of Split, which he completed in 2008.
