Cincinnati, Aug 19 (IANS): Second seed Naomi Osaka of Japan survived a scare as she overcame American teenager Coco Gauff 4-6, 6-3, 6-4 to advance to the third round in the WTA event here.

Naomi, playing her first event in the American hardcourt circuit in the lead-up to the US Open, was a set and a break down on Wednesday but quelled Coco in their second-round encounter at the joint ATP, WTA sanctioned Western & Southern Open.

World No1 Ashleigh Barty of Australia too reached the third round with a 6-4, 7-6(3) win against Great Britain's Heather Watson while defending champion Victoria Azarenka of Belarus beat Alison Riske 6-2, 7-5 to reach the next round. Third seed Aryna Sabalenka of Belarus was stunned 5.7, 6-2, 7-6(4) by Paula Badosa of Spain in a Round of 32 clash.

But the spotlight was on Naomi, who has not played many matches this season as she had pulled out of the French Open and Wimbledon citing mental health issues. She was also playing her first match here after getting a bye in the first round. And her rustiness showed as Coco won the first set.

The American broke Naomi's serve early in the second set to go ahead 1-3 but the Japanese star fought back brilliantly, won the next five games, and served superbly in the third set -- she dropped just one point in the entire decider -- to emerge victorious in two hours.

"Whenever I play [Coco], it's definitely always very tough," Osaka said after her win. "I felt like today the match was very serve-reliant, so I'm very happy that my first serve didn't let me down," she was quoted as saying by th eWTA Tour.

"I would have been really happy if I was able to turn things around in the first set, but I'm glad that I was able to do it in the second set. I was more just examining her and trying to stay calm. I felt like the last time I played her in Australia, I was definitely not calm at all. Just trying to keep a level head and figure out like what I could do better during the match."

Former World No 1 Angelique Kerber of Germany defeated Elina Svitolina 7-5, 2-6, 6-for a spot in the Round of 16.

Elina came into Wednesday's encounter with a 9-5 lead in head-to-head having won her past seven matches against Angelique. But the German three-time Grand Slam champion could not be denied on Wednesday as she defeated her opponent from Ukraine in just over two hours. Angelique has now won 12 of the 13 matches since winning her 13th career title at Bad Homburg, Germany, in June this year. She had reached the semifinals at Wimbledon.

In other second-round matches, Karolina Pliskova of the Czech Republic beat Yulia Putintseva of Kazakhstan 6-2, 6-2; Belinda Bencic beat Shelby Rogers of the United States 7-6(1), 6-1; Ons Jabeur of Tunisia defeated sixth seed, Iga Swiatek of Poland 6-3, 6-3, while Spain's Garbine Muguruza beat Carolina Garcia of France 6-4, 6-3.