Former British No.1 Greg Rusedski has warned Andy Murray he must be 'realistic' at the French Open next week.

Murray has struggled on clay surfaces throughout his career and Rusedski has told the British public not expect a British winner at the French Open just yet.

Murray has earned his highest seeding for a grand slam at No3 in this morning's draw after securing a hat-trick of ATP titles to continue last year's rapid climb up the rankings.

But for all his progress, doubts remain about the 22-year-old Scot's ability on the game's slowest surface, with his best effort so far only taking him as far as the quarter-finals in Monte Carlo last month.

"I think Andy has got to be realistic going into the French Open and for me I think if he can make it into the quarters or semis then that would be a great achievement," said Rusedski, who reached the US Open final in 1997.

"He has been playing well and obviously did well in Monte Carlo and Madrid but I don't think anyone can stop Rafael Nadal the way he is playing at the minute.

"Andy has done fantastically to become the world number three but I can't see how he can challenge Rafael or Novak at the French open.

"So if he can come away having made it through to the quarter finals on clay then that would be a great achievement."

Rusedski is backing Spaniard Rafael Nadal to clinch the title at Roland Garros this week.

"What Nadal does on clay is superhuman," he said. "His record is unmatched and it's going to take something fairly special to derail his challenge. Rafa is the clear favourite for the event."