BEIJING -- Aryna Sabalenka kicked off her reign at World No.1 with a 6-1, 6-2 victory over Sofia Kenin on Sunday in the first round of the China Open. Playing in her first tournament since the US Open, Sabalenka needed just 67 minutes to avenge her loss to the American earlier this season in Rome. 

Sabalenka will face either Katie Boulter or Magdalena French in the second round. 

Sabalenka fired 22 winners to just nine unforced errors against Kenin, who managed just seven winners of her own. It was a near-perfect performance for the reigning Australian Open champion, who did not face a break point while breaking Kenin four times. 

"Honestly, I didn't expect to play that good on my serve," Sabalenka said. "On practice, it didn't work that well. But I was super happy that I was able to bring that level on my serve today. I think it's helped a lot.

"I think she didn't even expect that great serving game. So I think that was the key of today's match."

More from Beijing:

No.28 Anhelina Kalinina earned her first Top 10 win of the season after defeating No.8 Marketa Vondrousova 1-6, 6-4, 6-1 in the first round of the China Open. 

A finalist in Rome earlier this year, Kalinina will face Australia's Daria Saville in the second round. 

The loss is a minor setback for Vondrousova's WTA Finals qualifying campaign. The Czech entered the tournament at No.6 on the Race to the WTA Finals with 3,661 points, with a chance to seal her spot in Cancun this week. Looking to chase her down this week are Ningbo champion Ons Jabeur and Guadalajara champion Maria Sakkari, who sit at No.8 and No.9 in the Race, respectively.

Kalinina and Vondrousova split their two previous meetings, but Sunday's showdown was their first at the tour level. Vondrousova dominated the first set and came within a point of holding a break lead in the second set. But in a pivotal pair of games, Vondrousova failed to convert one of three break points and was then broken at love three games later. 

With a viable comeback in the cards, Kalinina took control of the match. After breaking for a 4-3 lead in the second set, Kalinina lost just two games for the remainder of the match.