Top-ranked Aryna Sabalenka moved closer to clinching the year-end world number one ranking on Sunday by dominating Greece’s Maria Sakkari in a group-stage opener at the WTA Finals. The 25-year-old from Belarus, who captured this year’s Australian Open title, fired six aces and 17 winners while saving all five break points she faced to dispatch Sakkari 6-0, 6-1 at the season-ending event in Cancun, Mexico. Sakkari saved three match points to hold serve in the penultimate game but fell after 74 minutes.

“It wasn’t as easy as the score showed,” Sabalenka said. “I just tries to stay focused, tried to control myself in this match, doing everything I can to win.”

American Jessica Pegula defeated Kazakhstan’s Elena Rybakina 7-5, 6-2 in 83 minutes in the other singles group stage match at the $9 million outdoor hardcourt showdown.

Two groups of four players will compete in round-robin matches through Friday with the two top finishers in each group advancing to Saturday’s semi-finals. The final will be next Sunday.

Sabalenka is trying to hold off second-ranked Iga Swiatek, the reigning French Open champion from Poland, to claim the year-end crown taken last year by four-time Grand Slam winner Swiatek.

Sabalenka can clinch the year-end top spot by going 2-1 in the group stage and reaching the final no matter what Swiatek does.

The triumph by Sabalenka ensures Swiatek must win the title to have a chance at the year-end top spot.

Sabalenka was the runner-up in last month’s US Open and reached the semi-finals at Wimbledon and the French Open. She also won WTA titles this year at Madrid and Adelaide.

Sabalenka became world number one after her run to the US Open final in September, ending Swiatek’s 75-week rankings reign after her debut at number one in April 2022.

“It’s good to reach one of your goals but you still need to work hard and bring your best tennis,” Sabalenka said. “When you reach number one I feel like you have this huge target on your back.”

Monday’s opening matches in the other group send Swiatek against reigning Wimbledon champion Marketa Vondrousova of the Czech Republic and 19-year-old American Coco Gauff, the US Open champion, against Tunisia’s Ons Jabeur.