AFP, Singapore :Spain’s Garbine Muguruza marched into the semis of the WTA Finals in Singapore on Friday after beating Czech Petra Kvitova 6-4, 4-6, 7-5 to sweep her group.The world number three had to hang tough against Kvitova but she is now on course for a title clash with Maria Sharapova, who also won all three of her group matches.”Petra is an amazing player, I think today she was doing great. I obviously was so nervous, she makes me play, really concentrate and I have to give my best, but I’m super happy of this ending,” Muguruza said.”You know to be here for me is a great pay-off after the whole year, and hopefully I can continue winning and playing like this.”Kvitova’s fate is still in the balance and she needs fellow Czech Lucie Safarova to beat Angelique Kerber in straight sets in Friday’s second White Group match to reach the semi-finals.Muguruza, at 22 the youngest player at the year-ending tournament, will play the experienced Agnieszka Radwanska in the semi-finals.Sharapova, who is also unbeaten in Singapore and has looked revitalised after months out with injury, awaits the second-ranked player in White Group.Muguruza didn’t have it easy against two-time Wimbledon winner Kvitova and she had to dig deep in a messy first encounter with the Czech.The two ended with a shared total of 15 service breaks after see-saw battles in the second and third sets.With five breaks in the final set alone, Muguruza grabbed the crucial break for 6-5 and it took her four match points before she closed it out with a lunging volley.