Ko said a different wind direction made a tough start to the day.
"I knew the holes would play quite differently but with the first few holes all into the wind and raining from yesterday afternoon and overnight I think definitely made the course a lot softer and hence made it a lot longer…I was just trying to grind my way out there," she said after her round.
"I feel like I could have shot a lower score but at the same time it could have been a lot worse so I'll take what I have today."
Only two players shot under the card in the third round with Kim the only player to score in the 60s with a four-under 67.
Ko, who last claimed a major in 2016, said she just had to stay patient heading into the final round of a major in 2020.
"Sometimes you keep going on a par train and you think 'when is there going to be a good turnaround?'
"Around a course like this and especially at majors pars are sometimes not a bad score," she added.