Garbine Muguruza beat Anett Kontaveit in straight sets to win her first WTA Finals title in Guadalajara, Mexico.

Sixth seed Muguruza won 6-3 7-5 to become the first Spaniard to win the season-ending finals, beating Estonian eighth seed Kontaveit for the second time this week.

The two-time Grand Slam champion will rise to third in the world rankings on Monday.

"Right now, I feel extremely happy and relieved," said Muguruza, 28.

"It's a tournament that I've struggled at the beginning, then I managed to play well.

"I think I'm staying composed a little bit now because it means really a lot to me to win such a big, big, big tournament in Latin America, here in Mexico. I think it's just perfect."

Victory marked former world number one Muguruza's 10th career WTA singles title.

She had ended Kontaveit's 12-match winning streak in the round-robin stage of the tournament, before prevailing again in the final, winning four straight games to take the trophy.

"I'm just very happy I proved to myself once again I can be the best, I can be the maestra, as we say in Spanish," she said.

"That puts me in a very good position for next year, a good ranking... It's just the pay-off for such a long year. My team and I worked hard. It pays off. It just shows us that we're doing [things] the right way.

"This trophy, like right now here, these are the best feelings. Not even the ranking. Just to actually touch this and I take it home, it's in the story, it's in my curriculum. It's the way of, like, 'I did it.'"