The 22-year-old Spaniard, who recently rose to number three in the world rankings, pulled off a 6-3, 7-6 victory in the end-of-season event which features the world's top eight available players.

Muguruza and compatriot Carla Suárez Navarro were beaten in the doubles by Šafářová and American Bethanie Mattek-Sands yesterday, with that match ending with an identical 6-3, 7-6 scoreline.

The Venezuelan-born player, beaten in the Wimbledon final by Serena Williams this year, was delighted to turn the tables in one-on-one action.

"It was a very tough match, I was very nervous as it was my first time here playing singles," she said after a victory over an opponent who had knocked her out at the quarter-final stage of this year's French Open.

"At the French she played an amazing match - I played a good match also - but this time, I don't know, I just wanted to win so much.

"I was fighting and concentrating very much."

Muguruza was broken at the start of the second set but was not trailing for long after a successful Hawk-Eye review saw her strike back in the sixth game.

Her victory means she has made the perfect start to the White Group - one of two four player pools at the tournament which will both send two players into the semi-finals.

In the other White Group match, twice Grand Slam semi-finalist Angelique Kerber of Germany saw off Czech star Petra Kvitová 6-2, 7-6.

Two-times Wimbledon champion Kvitová, who had spoken about battling jet-lag before the hard-court clash at the Singapore Indoor Stadium, failed to get going in the first set and now faces an uphill task to qualify for the last four.

Tomorrow is due to see the second Red Group matches, with Poland's Agnieszka Radwańska set to collide with Italian Flavia Pennetta in a must-win affair for both players after they each lost their opening contests.

Romanian Simona Halep, meanwhile, and Russia's Maria Sharapova will both be looking to make it two wins from two when they clash in the second scheduled game.

This year's tournament does not feature world number one Serena Williams, who won three of this year's four grand-slams, after the American opted to withdraw to recuperate from injuries.

Meanwhile, there was an opening doubles victory for Chinese Taipei pair Chan Hao-ching and Chan Yung-jan, who defeated France's Caroline Garcia and Slovenian Katarina Srebotnik 6-4, 7-6 in the White Group.

The doubles tournament also features the top eight teams, again split between two groups.


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