On the brink of even more golf history, Lydia Ko plays it cool

— -- SAN MARTIN, Calif. -- Lydia Ko has got all the shots, on and off the course, from curling in putts to cutting up with reporters, delivered with an ease that belies her age.

As the 19-year-old was being interviewed Saturday following the third round of the U.S. Women's Open at CordeValle, a journalist asked Ko about her routine to prepare for pressure-packed Sundays.

"I go partying," Ko said, "partying all night and come straight to the course."

The joke drew laughs like her game attracts raves, although Ko would have to start doing stand-up for her humor to wow at the same level as her golf.

Having won two of the past three women's major championships, Ko is in excellent position to make it three out of four. The world's top-ranked player shot a 2-under 70 to take a 1-stroke lead over Eun Hee Ji, who won the 2009 U.S. Women's Open, and Sung Hyun Park, at 7-under 209 after 54 holes.

Everyone will be chasing Ko, who already has caught most of her sport's significant records for success at an early age and is poised, if she closes out a victory in the women's game's oldest major, to collect two others.

Appreciating all of Ko's achievements can feel like being a kid with too many toys under a Christmas tree.

Ko won an LPGA event at 15, became the No. 1 player in the world at 17 and, when she won the 2015 Evian Championship, surpassed Morgan Pressel as the youngest winner of a women's major. Thirty-seven LPGA events have been won by teenagers, with Ko accounting for 13. The next-best teen record belongs to Lexi Thompson with four wins.

If Ko (19 years, 2 months, 16 days) wins Sunday, she will break Inbee Park's mark as the youngest winner of the U.S. Women's Open by nine months. She would become the youngest golfer to win a third major, eclipsing Tom Morris Jr., who was slightly more than two months older than Ko when he won the 1870 Open Championship.

Ko is a rare comet of a golfer, but Saturday night was going to be oh, so ordinary.

"The best thing is to not get out of your routines," Ko said. "It doesn't matter if it's the first day or the last day or the third day or an extra day. I love my sleep, so I know that I'll have a good night's sleep. But nothing different. Nothing special to eat. I want my mom's cooking, and that's it."

Ko's putting, usually a strong suit, has lived up to its reputation the past two days at CordeValle. She has needed only 25 putts in each of the second and third rounds. A Friday 66 allowed Ko to cut into a 9-shot deficit she had to Mirim Lee after a first-round 73, and being handy on the greens kept her under par Saturday.

In particular, three long putts -- hard-breaking 25-footers for birdie on Nos. 3 and 13, and a par save of similar length on No. 14 -- were pivotal.

"I wasn't expecting that one to go in," Ko said of the birdie effort at the 13th, which she thought she had misread. "I was walking a little bit and then I saw the ball drop, so it kind of took me by surprise. It was a lucky one. But I almost think my par on 14 was the more meaningful of the two."

Ko did a minor fist pump after sinking the putts at the 13th and 14th. Demonstrative is normally not her style, but looks can be deceiving.

"I look a lot calmer than what goes on in the inside," Ko said. "I definitely do get nervous, but I think that's part of it. I think nerves are good because it means you're excited. You're ready. It means a lot to you."

As three-time Masters champion Jimmy Demaret once said, the key is to have the butterflies flying in formation.

"I guarantee Lydia feels the same things we do," said Brittany Lang, whose third-round 68 moved her into a tie for fourth, 2 strokes behind Ko. "She does a better job controlling them. She gets back to what she's doing, and she executes. It's impressive. She's the master of it, it's unreal."

The last time Ko had the 54-hole lead at a major, last month's KPMG Women's PGA Championship at Sahalee Country Club near Seattle, she went out on Sunday and shot 67 and still lost -- to fellow teenager Brooke Henderson in a playoff after the Canadian closed with a 65.

"I thought there were so many positives, from that final round at Sahalee," Ko said. "All I can do is try my best. If somebody plays better than me, I can't do much about it. That was a perfect example of that. Brooke played so impressively on that Sunday. And for her to win the playoff with a birdie, I think that just kind of summed up her day."

Ko missed a short birdie putt on the 71st hole at the Women's PGA, a putt that would have salted away a third straight major title. But even the greatest champions don't make everything, and they tend to dwell on their successes, not their failures.

Although not yet 20, Ko has a stunning reservoir of grace under pressure going back to childhood. When Ko was only 11 she faced an older opponent in the final of the New Zealand Women's Amateur. Ko didn't win the match but left an indelible impression on those who watched with her cool, which has become such a trademark during her precocious career.

"Confidence is an earned commodity," Fox golf analyst Paul Azinger noted during Saturday's broadcast, "and she's earned it through achievement."

Hard work, more than most could imagine, has brought Ko to this point, not that there aren't some occasional diversions. In fact, on vacation in her native South Korea last December, Ko did stay up almost all night attending with her sister and friends a Psy concert. The "Gangnam Style" performer's show didn't start until midnight.

"The concert started at 12 and ended at 2, and there was an encore that went for an hour," Ko said. "I ended up coming home at 5 a.m. My throat was a little weird the next day, and I don't think I've sweated that much in my life. I had a seat but there was no point in having one because you were jumping up and down the whole time. I had a good time."

The atmosphere at CordeValle on Sunday will be a bit different, but fun is fun.