She said her ball-striking was helping her build confidence.
"I've been hitting the ball pretty good and was hoping to continue to do that over this weekend, and hoping a few putts would drop. I holed a few good putts but I think ball-striking has been the key for me the last few days. I'm going to hope again that it's good for tomorrow…staying patient is a big key on this golf course," Ko said after her third round.
"When you play well, I think day-to-day things don't really change much but you're feeding of confidence and you're feeding off the belief you can shoot low scores. That's been the approach that's been working so far this week as well."
The round of 64 keeps Ko in top position to claim the Vare Trophy honours for lowest scoring average with five rounds remaining in the season. The top two players in the world, Jin Young Ko and Nelly Korda, have not played enough rounds to be up for the award.
If Ko claims the first Vare Trophy award of her career she'll move to 20 points for Hall of Fame eligibility, putting her seven points shy of an automatic spot in the Hall of Fame.
A solid round tomorrow will also guarantee Ko breaks into the top-10 in the all-time money list on the LPGA. The 24-year-old sits in 11th position on US$12,128,964 over 197 events, just $5,876 behind American Paula Creamer in 10th.