But to be 14-under heading into the weekend, and one shot off the lead in a world-class field is a stunning result for the 15-year-old, who is well in the hunt to claim her third national open championship in the space of a year.
Ko too had to remind herself to keep her second round score in perspective.
"I shot a four-under which is a good score, but I know personally after such a great round yesterday when all the putts were going in I did feel like 'oh why aren't they going in like yesterday?' " she said.
"But I am happy, I have played pretty good golf over the first two days and hopefully I can keep striking the ball well over the weekend."
The youngster said she was unaffected by the obvious pressure on her shoulders after her star showing in the opening round.
Starting in the morning groupings, South Korean star Jiyai Shin laid down a challenge firing a six-under par 67 to follow her opening 65 and surged ahead.
However Ko, the overnight leader, wasted little time in catching Shin, rattling off four birdies over the first nine holes, before taking the outright lead at 15-under with another birdie on the par-4 12th.
But a bogey on the 14th saw Ko draw level again with Shin, before the pair were overtaken by Uribe who powered home with four birdies on the back nine.