"Her health is going in the right direction, Justine is feeling much better," her coach Carlos Rodriguez said. "She has less problems focusing on things and her moments of weakness are disappearing. These are encouraging signs. We see light at the end of the tunnel but with this virus we still can't be certain.

"We stay cautious, hoping she'll have recovered before the Olympic Games (next month)."

Rodriguez said changes had been made to Henin-Hardenne's physical training schedule.

"Her blood gets examined on a regular base to keep up with the evolution of the virus, but what's most important is knowing how she's feeling," he said. "Her level of play is good."

Henin-Hardenne, 22, lost in the second round of this year's French Open and was forced to pull out of Wimbledon last month.