Cleveland – Coming into Saturday’s U.S. Women’s Amateur semifinal match, Lydia Ko and Ariya Jutanugarn were ranked No. 1 and No. 2, respectively, in the World Amateur Golf Ranking.

So it was no surprise that the two played a close match on the 6,512-yard, par-72 William Flynn design at The Country Club, with Ko, 15, of New Zealand, winning, 3 and 1, to advance to Sunday’s scheduled 36-hole championship final. Ko will face Jaye Marie Green, 18, of Boca Raton, Fla., who is ranked No. 7 in the WAGR.

“I’m really excited and blessed to be playing the world No. 1,” said Green, after eliminating 20-year-old Nicole Zhang, 2 up, in the other semifinal match.

But it was the Ko vs. Jutanugarn match, their first face-to-face meeting on the golf course, that took center stage on a blustery, ominous-looking day.

“I wanted to try my best and not be disappointed,” said Ko. “It’s pretty awesome to get to the final because this is the greatest amateur event.”

At 15 years, 3 months and 18 days, Ko is the second-youngest finalist in Women's Amateur history. If she wins, she will also become the second-youngest champion. Both records belong to Kimberly Kim, who won in 2006 at 14 years, 11 months and 21 days.

Ko knew going into the match that she had her work cut out for her. That’s because she learned that Jutanugarn, 16, of Thailand, could boom the ball off the tee.

“Ariya goes about 290 [yards] off the tee and I go 250,” said Ko, who is competing in her second U.S. Women’s Amateur. “When I heard she goes around 290, I was like, ‘Whoa.’”

Jutanugarn, who won the 2011 U.S. Girls’ Junior, did indeed outdrive Ko by some 40 yards on the majority of the holes. But the unflappable Ko, who reached the semifinal round of this year’s U.S. Girls’ Junior, persevered with poise and a strong finesse game, which included a total of just 23 putts.

“She’s an amazing putter,” said Jutanugarn, who was the stroke-play medalist at this year’s U.S. Girls’ Junior but lost in the semifinal to eventual champion Minjee Lee.

Ko shot the equivalent of six under par for the 17 holes with the usual match-play concessions. Jutanugarn played one-under-par golf.

Ko’s dazzling putting performance began on the 371-yard, par-4 fourth hole when she drained a 30-foot birdie putt from below the hole to grab a 1-up lead. It was an advantage she would never lose. On No. 5, the two traded 6-foot par putts to halve the hole. On No. 8, a 529-yard par 5, Ko made a 21-foot birdie putt, but Jutanugarn halved the hole by converting a 12-footer.

Jutanugarn had a chance to even the match on the 379-yard, par-4 10th hole but she pulled her 8-foot birdie attempt.

“I missed some short putts,” said Jutanugarn.

“I don’t think she had one of her best putting days,” said Ko. “For me, it was one of the best putting days I ever had.”

Ko capitalized on another Jutanugarn mistake on the 146-yard, par-3 11th hole. Ko, who registered 12 greens in regulation, sank an 18-foot birdie putt that broke 2 feet to the left. Standing over an 8-footer to halve the hole, Jutanugarn pushed her putt to the right, and Ko was 2 up.

Jutanugarn bounced back on the next hole, carding her third of four birdies by knocking in a 10-footer.

The key moment of the match came on the 410-yard, par-4 15th hole. Jutanugarn, who reached 14 greens in regulation, stuck her approach shot to within 3 feet of the flagstick. Ko’s approach stopped short of the green, roughly 45 feet from the hole. The hole appeared to belong to Jutanugarn. But Ko made an improbable chip-in that forced Jutanugarn into a must-make situation. She converted, but instead of winning the hole, she halved it.

“Her short game was perfect,” said Jutanugarn.

Said Ko of the chip-in: “She hit it to 3 feet and I knew with the lead I had to play aggressive there. My mom (Tina, her caddie) said, ‘Don’t hit it super hard, and I didn’t.”

Mist was constant throughout the round. Ko believed it to be to her advantage because she often plays in rainy weather in New Zealand. Her coach, Guy Wilson of the New Zealand Institute, gave her a pep talk on the phone after Friday’s quarterfinal round. He told her that she could play with anyone in unkind weather conditions.

“I’m starting to believe him,” said Ko.

On the 450-yard, par-5 16th hole, Ko capitalized on another Jutanugarn error. Jutanugarn, who hit 11 of 13 fairways, pushed her tee shot into the right rough and was forced to punch out short of the green. In the meantime, Ko reached the green in two and was looking at an eagle putt of nearly 60 feet. Jutanugarn wound up three-putting to bogey the hole; Ko won the hole with a 9-foot birdie to restore her 2-up advantage.

“That really hurt me,” said Jutanugarn.

Ko closed out the match at the 387-yard, par-4 17th hole after another Jutanugarn miscue. With 107 yards to the hole, Jutanugarn went for the flagstick, which was tucked left. Her shot missed the green to the left and bounded down the slope. Ko knocked her approach shot to 8 feet above the hole. After Jutanugarn’s next shot stopped some 60 feet from the hole, she conceded and the two players embraced.

“I played OK,” said Jutanugarn. “The last two holes I made some mistakes. It was fun and exciting to be here. I didn’t really feel any pressure playing Lydia. I just missed some short putts.”

Ko, who won the 2012 New South Wales Open at 14 in January to become the youngest person, male or female, to win a professional tournament, said she was “stoked” to move into the final. She didn’t know much about her opponent.

“I have a 50-50 chance,” said Ko of Sunday’s scheduled 36-hole final. “I’m pretty confident. Sometimes luck is with you, and sometimes it’s not.”

The world’s No. 1-ranked amateur player has had a little more than luck on her side. Come Sunday, she will try to prove it again.