Garbine Muguruza has beaten sixth seed Angelique Kerber 6-4 6-4 in her second round-robin match at the WTA Championships in Singapore.

Muguruza, who is the first Spaniard to take part in this event since 2001, opened her tournament with a 6-3 7-6 win over Lucie Safarova on Monday.

That has now become two wins from two games following a comfortable victory over Germany's Kerber in the White Group.

Both players secured breaks in the opening four games to leave the first set on serve at 2-2, but a vital break at 4-4 allowed Muguruza to serve out the opener.

Kerber started the second set on the front foot, but another Muguruza break at 2-2 allowed the Spaniard to take control and she eventually won the second 6-4 following another exchange of breaks.

Earlier on Wednesday, Petra Kvitova earned her first win of the competition by beating Safarova 7-5 7-5.