Michael Stich believes Rafael Nadal has no chance of following up his fourth French Open win with victory at Wimbledon.

On the day Nadal opens his singles challenge in the Artois Championship at Queen's Club, former Wimbledon winner Stich accused the Spaniard's rivals of conceding too easily against the king of clay at Roland Garros.

But Stich reckons it will be a different matter when it comes to grass, a surface on which Nadal has proved more vulnerable to attack, even though he reached the past two finals in SW19.

"Nadal deserves to win the tournament at some stage, there's no doubt about it," said Stich. "And his chance to win on grass is higher than his chance to win on hard court, because I believe that is his weakest surface.

"But I think that Wimbledon this year is not going to be a Nadal year.

"I was very impressed with the way he played in Paris but I was disappointed at how his opponents handled matches against him. You sometimes get the feeling on clay that players go on court against Nadal and they don't believe that they really have a chance. They give in too easily.

"Remember when Roger Federer was so incredibly dominant that his opponents came off court and only praised his play and said how great he is?

"That seems to happen now with Nadal on clay. But it is not going to happen on grass, a very special surface.

"The French Open worked perfect for him. It was good weather and the balls were very fast, coming off his racket very quickly.

"But at Wimbledon you always have that thing where if it's raining for three days you must come on and off the court again and again.

"It's a very different game and Nadal's opponents are not going to give in straight away. There will be some who take more of a chance against him."

Stich, winner of the men's singles title at Wimbledon in 1991, was set to get some idea of whether Nadal had successfully carried his form from the Paris to London when the 22-year-old left-hander went up against Swedish veteran Jonas Bjorkman on Centre Court at Queen's.

Nadal, the top seed, reached the quarter-finals in his two previous Artois appearances. Doubles specialist Bjorkman, 36, made the Wimbledon semi-finals two years ago.

It had the makings of an intriguing match although, ominously, Nadal made a swift exit from the doubles in gathering gloom last night when he and Mariano Hood lost 7-6, 7-5 to Fernando Gonzalez and Nicolas Lapentti.

Also on Centre Court today, Andy Roddick was beginning his defence of the Artois title against fellow American Robby Ginepri. In doubles action, Andy Murray and Daniel Vallverdu were playing Bjorkman and Kevin Ullyett for a place in the quarter-finals.

Meanwhile, James Ward's hope of a Wimbledon wildcard have been dashed. The 21-year-old Londoner was hoping his fighting performance against former world No1 Marat Safin on Monday would reap a prized reward. But he has to be content with entry direct into the qualifying competition, which begins at Roehampton on Monday.

Six British players did receive wildcards into the main draw for Wimbledon, which starts on 23 June.

Jamie Baker and Alex Bogdanovic go straight through into the men's singles, along with former semi-finalist Xavier Malisse, of Belgium, Frenchman Jeremy Chardy and Canada's Frank Dancevic.

In the women's singles, Elena Baltacha, Katie O'Brien, Melanie South and Naomi Cavaday receive wildcards along with Poland's Urszula Radwanska and Carla Suarez Navarro, of Spain.

Five more wildcards, three for men and two for women, are still to be allocated.