Belarus' Aryna Sabalenka serves to Britain's Katie Boulter during the women's singles second round match at the China Open tennis tournament in Beijing on Oct 3, 2023. (PHOTO / XINHUA)

World number one Aryna Sabalenka powered past Maria Sakkari 6-0 6-1 at the season-ending WTA Finals in Cancun, Mexico on Sunday where the Belarusian is looking to secure her top ranking after a spectacular season.

Two of Sakkari's three wins in nine meetings with Sabalenka had come in previous editions of the season finale but the Greek world number nine was no match this time for her opponent, who moved to the top of Group A alongside American Jessica Pegula.

Sabalenka converted five out of nine breakpoint chances and won 11 games in a row during the clash to finish in 74 minutes.

Australian Open champion Sabalenka overtook four-times major champion Iga Swiatek and captured the top ranking after the US Open and will retain the number one spot if she goes undefeated in round-robin play or makes the final

"She's an amazing player. She's always fighting for every ball," Sabalenka said.

"I knew no matter what the score is that she would fight for it. That's what makes her a really tough opponent.

"You know against Maria, any time she can come back. You give her a little bit and she'll take that and keep fighting. I just tried to stay in the moment."

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Australian Open champion Sabalenka overtook four-times major champion Iga Swiatek and captured the top ranking after the US Open and will retain the number one spot if she goes undefeated in round-robin play or makes the final.

Earlier, Pegula won 10 of the last 12 games to get past an error-prone Elena Rybakina and notch a 7-5 6-2 win.

Jessica Pegula, of the United States, serves to Madison Keys (not in photograph), of the United States, during the fourth round of the US Open tennis championships, on Sept 4, 2023, in New York. (PHOTO / AP)

The big-serving Rybakina looked poised to capture the first set when she stepped to the service line leading 5-3 in the opener but Pegula raised her return game for a crucial break.

Pegula used that momentum to close out the set by winning four straight games and her clean ball striking overwhelmed the Kazakhstani, who tallied 35 unforced errors in the match.

The big-serving Elena Rybakina looked poised to capture the first set when she stepped to the service line leading 5-3 in the opener but Jessica Pegula raised her return game for a crucial break

"I feel like she just made a couple careless errors and I was able to take advantage of it at the right time and ride that momentum all the way through the second set," Pegula told Tennis Channel after securing the win.

"I thought I was returning really well, reading her serve a little bit more, and was able to play some good tennis."

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Pegula, who is seeded fifth, will on Tuesday face eighth seed Sakkari of Greece.

The Oct 29 to Nov 5 Finals features the top eight singles players and doubles teams in the world.