WTA Tournament of Champions: Carla Suarez Navarro wins in straight sets to make semis

Carla Suarez Navarro sealed her place in the semi-finals of the WTA Tournament of Champions with victory over Tsvetana Pironkova in Sofia on Friday.

The Spaniard needed to come out of the round robin stage of the tournament with a straight-sets victory to guarantee her place in the last four, and she was able to do exactly that, prevailing 7-6 (7/2) 6-1.

However it was not plain sailing for the fifth seed, as Pironkova, playing in front of her home crowd, was highly competitive in the first set.

The Bulgarian broke Suarez Navarro's serve on two occasions, going 3-1 ahead and then earning two set points at 6-5, but she as unable to make her advantage count.

Once she surrendered the tie-break her game unraveled and she was powerless to prevent her opponent racing to a 5-0 lead in the second set before closing out the victory in routine fashion.

Also through to the semis from the Sredets group is Germany's Andrea Petkovic, who had already sealed her spot on Thursday.

From the Serdika group, Spain's Garbine Muguruza clinched her spot in the semi-finals with a 6-3 7-5 victory over Alize Cornet of France.

The victory made it three wins from three for Muguruza, who will now face Petkovic in the final four.

Muguruza said: "In the second set, I was more nervous because I thought 'I am so close to win'. Also, she played better than in the first set."

Italy's Flavia Pennetta was the final player to book her semi-final spot, beating Karolina Pliskova 6-1 6-3 to set up a clash with Suarez Navarro.

Pliskova was substituting for Ekaterina Makarova, who withdrew from the tournament with a back injury on Thursday.