Garbine Muguruza says the fast turnaround from hardcourts to clay was behind the injury she sustained in Charleston.
The two-time Grand Slam winner was absolutely cruising against Yulia Putintseva in the third round, bageling the first set and level at 2-2 in the second.
However, despite her dominance, Muguruza was forced to withdraw from the match due to 'sharp pains' in her legs.
“I was already feeling some pain in my first match," Muguruza said. "The switch of hard courts to clay was tough, and in a very short amount of time.
“I started very well, and all of a sudden I felt a sharp pain in my leg, and it got worse.
"I didn’t want to continue without playing my best tennis. It didn’t make sense to me.”
Muguruza will now take some time to be assessed before making a decision on her scheduling, but being fit for Roland Garros would appear to be a priority for the Spaniard.
Putintseva, meanwhile, understandably admitted she did not feel worthy of her place in the quarterfinals.
“First of all, she was playing really great tennis since the first point.
“I tried to fight back, I tried to do my best, and in the second set I could at least make it to be even.
"But for now I don’t feel like I deserve this, to go through. I wish her a speedy recovery – she’s having a great season.”
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