Ruoning Yin hit the ball so poorly on the practice range that she wasn’t expecting much Thursday in the CME Group Tour Championship. The big surprise was a 9-under 63 and a share of the lead with Nasa Hataoka in the chase for the $2 million prize.

Yin opened with five birdies through eight holes, played bogey-free and got a bonus at the end when her fairway metal took a good hop off the collar and onto the green at the par-5 17th for one last birdie.

Hataoka and Yin led by one shot over Minjee Lee, who made a 30-foot birdie putt from off the 18th green at Tiburon Golf Club.

“I do my warmup and I don’t feel today is the day,” Yin said. “I was not in the mood for chatting. After nine holes, ‘OK, 5 under. Maybe I shouldn’t talk that much.’ I think this course really suits me. The fairway is wide open. The greens are not that hard. It’s not that long.

“Just tried to hit every fairway, every green and make the putt.”

Hataoka began her round with 11 consecutive one-putt greens, three of them to save par. She was 8 under through 13 holes and then picked up one one more birdie at the easy 17th on the way in for her 63.