Karolina Pliskova continued her dominance of Garbine Muguruza Wednesday, opening her WTA Finals campaign with a battling 4-6, 6-2, 7-6 (6) victory over the Spaniard.

Czech third seed Pliskova, at 29 the oldest player in this year’s edition of the elite season-ending event, has now won nine of 11 career meetings with Muguruza, the latest putting her atop her round-robin’s group standings alongside Estonian Anett Kontaveit, who beat second-seeded Czech Barbora Krejcikova 6-3, 6-4.

After dropping the first set, Pliskova produced a superb serving effort to take the second, putting 16 of 18 first serves in play and dropping just two points on serve.

In a tense third set, Muguruza saved two match points while serving at 4-5 – the first with a service winner. But she was unable to capitalise on two break points that followed as they went to the tiebreaker.

Muguruza saved another match point to knot the decider at 6-6, but Pliskova won the next two to polish it off after two hours and 26 minutes when Muguruza belted a forehand wide.

The tournament was moved to Mexico from its usual home in Shenzhen, China, due to the coronavirus pandemic. The switch in venue means the tournament’s eight-strong singles field must adjust to the thin air of Guadalajara, which is around 5,100 feet (1,550 meters) above sea level.

Red-hot Kontaveit kicked off group stage action with her straight-sets win over French Open champion Krejcikova.

Estonia’s Kontaveit, the last player to secure her spot in the event, notched her 11th straight match victory, continuing a superb season that has seen her capture four WTA titles and rise to eighth in the world.

She needed just half an hour to pocket the first set – sealing it with an ace. Kontaveit, who didn’t face a break point, secured the match when Krejcikova fired a backhand into the net on match point.

“I’m definitely very thrilled to get the win, it was a very tough match,” Kontaveit said. “I think I managed to win a lot of points on my first serves once they actually went in.”

Krejcikova, the only reigning Grand Slam champion in the field, remained optimistic after a “difficult” match, noting that the round-robin format was more forgiving than a traditional tournament – and she has doubles to contest as well.

“I’m going to have another five matches that I can play, so I’m looking forward to that,” she said.