South Korea, who are fielding an entirely different rink to the one which claimed the title last year, inflicted the first defeat on the host nation in the evening session at the Shenzhen Universiade Sports Center.

Chi Un-gim's team, who had earlier beaten Australia 10-5, needed an extra end to overcome China 7-6 in a tense contest.

"We didn’t think too much about the results and I just focused on my last shot," said Chi.

"We feel we’re getting better and will do our best in the remaining games to get into the play-offs."

The victory leaves South Korea, China and Japan with a three win and one loss record after the first four sessions of play.

China began the day with a 7-6 victory over Japan, who later thrashed Australia 15-2.

In the men's tournament, China and South Korea remain the only two unbeaten teams after both sides recorded victories in the fourth session.

China thrashed Chinese Taipei 16-2, while South Korea swept aside New Zealand 8-2.

Both teams have four wins from their opening four matches.

Japan, who hammered Qatar 13-1, sit in third place.

The competition continues tomorrow with the latest round of matches in the women's and men's events.