SHENZHEN: Top-ranked Ashleigh Barty of Australia rebounded from a set down to win her debut match 5-7, 6-1, 6-2 over Belinda Bencic of Switzerland at the WTA Finals on Sunday.

Barty’s victory is her 53rd of the season, second most this season after Kiki Bertens with 54.

The 5-foot-5 Barty is a surprisingly potent server and ended her first career encounter against Bencic, also playing in her first year-end final, with her 10th ace of the match.

Earlier, Naomi Osaka extended her winning streak to 11 matches after defeating Petra Kvitova of the Czech Republic 7-6 (1), 4-6, 6-4 in the first of three round-robin matches on the day.

Osaka, the Australian Open champion, arrived in Shenzen having won the last two tournaments she played — in Osaka, Japan, and Beijing.

“Given that I do feel I’m a big-match player, there are some times when I play higher-ranked people and I don’t do that great,” said Osaka. “So I feel like this tournament is a big challenge for me. I think I’m not even really thinking of this tournament as the Finals, I’m just trying to continue on from where Beijing left off.”

The two-time Grand Slam champion failed to take advantage of two match points when serving at 5-2 in the third, but nailed down the victory on a third match point when serving in the 10th game.

Kvitova surrendered the encounter when she sailed a backhand crosscourt wide on the final point.

“I know how Naomi is playing, how confident she is from the past weeks when she played well in Asia,” Kvitova said. “So I did expect really tough match.

The only other time Osaka played Kvitova took place when the Japanese player captured this year’s Australian Open final but a score of 7-6 (2), 5-7, 6-4.