Great Britain's number two Heather Watson has conceded that she has still not fully recovered from her battle with glandular fever.
The 21-year-old spent 10 weeks on the sidelines before she returned at the French Open earlier this year. She lost in the opening round in Paris to Stefanie Vogele and fell at the same hurdle this afternoon at Wimbledon to Madison Keys, who recorded a 6-3 7-5 success.
Reflecting on her performance, Watson told BBC Sport: "I wasn't quick enough, my reactions were not there, I have to improve on getting the fitness, more work, more time on court. I'm only at 75 or 80%, I'm not at 100% yet.
"My legs feel strong, but its the recovery between points and my lungs that are the problem. Losing really hurts."
Watson will now turn her focus to the women's doubles and mixed doubles.