By Patrick Johnston
SINGAPORE (Reuters) - Debutant Garbine Muguruza made it three straight singles wins at the WTA Finals on Friday but the Spanish world number three was anything but storming through to the semi-finals after conceding an exhaustive schedule was taking its toll.
The Spaniard is also playing the doubles in Singapore with compatriot Carla Suarez Navarro and spent what should have been her rest day on Thursday battling past Taiwanese pair Chan Yung-jan and Chan Hao-ching to make the last four of that event.
The extra drain was clearly visible on the Venezuelan-born Muguruza but she showed great fight to edge double Wimbledon champion Petra Kvitova 6-4 4-6 7-5 to set up a last four clash with Agnieszka Radwanska on Friday.
"Well, for sure I'm tired today," Muguruza told reporters.
"It's going to a challenge for me to see how much my body can handle, because now I don't have a day off.
"It's great to be in my position, to be playing singles and doubles semi-finals, but it's going to be hard.
"I have to recover well and do everything possible to be ready for both matches."
The 22-year-old became the first debutant since Kvitova, who will play Maria Sharapova in the last four despite defeat, to win all three round robin matches at the elite eight woman end-of-season championships. The Czech achieved the feat in 2011.
The Spaniard's reward is a hectic Saturday beginning with a clash against Pole Radwanska at 1500 local time before an evening doubles against yet-to-be-determined opponents. The finals of both events take place on Sunday.
Muguruza only needed to take a set against Kvitova to ensure progression to the last four but she said there was never any intention to ease up after she accomplished that in the opener of what turned out to be a two-and-a-half hour slugfest.
"Well, I went to the court thinking that I want to win the match, not only a set or just to qualify," she said.
"I went there like, if you go on the court you have to go and win, not to be half half.
"So that's what I did. I had my good and bad moments, but I'm just happy that I've been through."
(Editing by Amlan Chakraborty)