PARIS, June 5 (Reuters) - Stanislas Wawrinka will draw on the advice and experience of the man who coached the only person to beat Rafa Nadal at Roland Garros when he meets the seven-times French Open champion in the quarter-finals on Wednesday.
The Swiss ninth seed, who has never taken a set off Nadal in nine encounters, is now coached by Magnus Norman who was in charge of Swede Robin Soderling when he upset Nadal in the fourth round in 2009.
The Spanish third seed had a straight sets win in the fourth round while Wawrinka experienced thigh problems in a five-set thriller against France's Richard Gasquet.
"I know it's difficult to play against Rafael on clay, and a five-set match, possibly," said Wawrinka.
"It's going to be difficult. I'll have to try and seize my chances and see what works out well for me."
Nadal is on a semi-final collision course with world number one Novak Djokovic, who faces German veteran Tommy Haas, at 35 the oldest man in a grand slam last eight since Andre Agassi at the 2005 US Open.
Women's defending champion Maria Sharapova, the second seed, opens proceedings with her quarter-final contest against 18th seed Jelena Jankovic of Serbia, who is looking to equal her best performance at Roland Garros.
Third seed Victoria Azarenka of Belarus, the double Australian Open champion, is bidding to reach the last four for the first time when she plays Russian 12th seed Maria Kirilenko. (Reporting by Julien Pretot; Editing by John Mehaffey)