Sweden's Robin Soderling, the player best known for being the first man to beat Rafael Nadal at the French Open, has retired from professional tennis because of a long-running illness.

Robin Soderling smiles during a news conference at the Royal Tennis Hall in Stockholm May 21, 2012.  [Photo/Agencies]

The 31-year-old, twice a runner-up at Roland Garros, had not played an ATP World Tour event since 2011 after contracting infectious mononucleosis, a viral illness also known as glandular fever.

"I've realised that I will not be healthy enough to be able to play tennis at the level I demand of myself," Soderling told tennis.se.

"For that reason I have decided to end my career as a professional tennis player."

"Thank you so much for all your kind words. So sad I won't play professional tennis again, but reading all your messages makes me feel a lot better," Soderling said later on his Twitter account.

Soderling spent 10 years on the Tour and rose to world number four. In 2009 he ended Nadal's domination in Paris with a stunning victory in the fourth round, only to lose to Roger Federer in the final. Until Novak Djokovic defeated Nadal in the 2015 quarter-finals, Soderling was the only player to have beaten the Spaniard at Roland Garros.

Soderling, who won 10 career titles including the 2010 Paris Masters, returned to the final at Roland Garros in 2010, losing in straight sets to Nadal. He won the 2011 Swedish Open shortly before being diagnosed with glandular fever – meaning that the final, where he defeated David Ferrer, proved to be the last Tour match of his career.