Sharapova and Muguruza sweep into last four of WTA championships

Garbine Muguruza overcame Petra Kvitova on Friday to maintain her 100 per cent record and claim the white group at the women's season ending championships in Singapore. In the red group, Maria Sharapova is also unbeaten.

Garbine Muguruza is competing for the first time in the elite eight woman WTA tournament. Reuters/Jeremy Lee

Second seed Muguruza booked her place in the semi-finals of the WTA Finals after beating Kvitova in three tight sets.

The 22-year-old Spaniard came through a nervy encounter with the Czech 6-4 4-6 7-5 after two hours and 33 minutes.

Muguruza will next play the fifth seeded Pole Agnieszka Radwanska who was runner-up in the red group behind the Russian Maria Sharapova.

"Petra is an amazing player," said Muguruza who is competing in her first season ending championships." I obviously was so nervous, she makes me play, really concentrate and I have to give my best.

"To be here for me is a great pay-off after the whole year, and hopefully I can continue winning and playing like this."

Despite the defeat the fourth seeded Kvitova advanced to a semi-final clash against Sharapova. The two-time Wimbledon champion progressed after compatriot Lucie Safarova - who had already been eliminated - beat Angelique Kerber in straight sets.

Of the four remaining players, 28-year-old Sharapova is the most experienced. She won the title in 2004 in Los Angeles and was the beaten finalist on two occasions in 2007 in Madrid and 2012 in Istanbul.

She'll start her semi against 25-year-old Kvitova with a slight advantage. The two have met nine times with the Russian emerging victorious on six occasions. Muguruza is on a roll against Radwanska. After suffering successive losses, Muguruza has won all four of their matches this year.