Poor service from Coria

To make matters worse, player and coach can't agree on what's wrong:

"Since my shoulder operation, I can't serve like before," said Coria.

"There's nothing physically wrong," dismisses Higueras.

"The problem with Guillermo is that he's afraid of making double faults," Higueras told French newspaper L'Equipe. "This fear makes him change his serve. It's solely a mental problem. He has to accept keeping the same movement, even if it means committing an unforced error," added the former coach of Carlos Moya.

"He's an anxious guy by nature. You can see that in other parts of his game, but it's more flagrant in his serve. And I repeat, there's no technical problem. In practice, he misses two serves out of 100."

One year ago at this time, it was Coria, not Nadal, who was tipped to win Roland-Garros, but the Argentine's service game has gone from bad to worse.

His 23 double faults against Kiefer equals his total in his third round loss at the Australian Open against Sébastien Grosjean and is only three shy of Marc Rosset's grand slam tournament record of 26 at Wimbledon.

His opponent Nadal is nonetheless wary:

"He'll have less pressure against me, so he should serve better."