Garbine Muguruza is eyeing the world's top ranking after climbing to third and making a winning start to her WTA Finals campaign.

The Spaniard claimed a 6-3 7-6 (7-4) victory over Lucie Safarova in Singapore on Monday in an ideal start in the White Group.

Muguruza, who moved into third in the rankings on Monday, said she was focused on maintaining – and raising – her level.

"I looked at it this [the rankings] morning on my phone. I was super happy. I think it's top three - something special," she said after beating Safarova.

"So, I don't know, I'm really motivated to stay there and hopefully keep climbing."

Muguruza broke serve three times against Safarova, but she failed to convert 12 of her break-point opportunities in the win.

The 22-year-old said she encountered some early nerves on her Finals debut.

"Well, it feels amazing to win my first match here in Singapore," Muguruza said.

"I was very nervous because this was the first match I played [here]. And they're all very tough. But I'm really looking forward to playing my next match. I feel more [comfortable] now in the tournament."

Muguruza added: "I was thinking to be consistent and concentrate on all the match and eventually I'll have my opportunity. So, that's what I did and I finally won the match."

The Wimbledon runner-up's next outing is a clash against Angelique Kerber on Wednesday.