With everything on the line, Punahou junior Andrew Chin faced a knee-knocking 11⁄2-foot putt on the 18th hole. Sink it and he’s the new Interscholastic League of Honolulu boys golf champion. Muff it and he’s saddled with the memory of a missed opportunity for the rest of his life.

Chin nailed it for the victory Thursday at the Turtle Bay Fazio Course. The putt finished off his par and it also put an end to an incredible comeback surge made by Buffanblu teammate Kyle Suppa, who wound up a stroke back.

As Chin stepped up to that final putt and the 10-footer before it, his mind went to work.

“I was thinking, ‘Don’t do anything silly,’ because I remember I.K. Kim missed a 1-footer to win (at the 2012 Kraft Nabisco Championship),” Chin said. “I didn’t want to do the same thing. On the first putt, I actually hit it a little low on the heel and it didn’t roll as far and stopped short. Then it was, ‘Oh, OK, I.K. Kim,’ so I said, ‘Take your time, do your thing and I hit a good putt.’ Thank goodness it went in.”

Chin shot an up-and-down, even-par 72 for the day after a dazzling 5-under 67 in the first round at Oahu Country Club on Monday to finish at 5-under 139.

“At No. 12, I made a bad wedge shot and made bogey,” he said. “I bogeyed 13, but made birdie on 14, so I was still five shots up and was like, ‘OK, just kinda gotta make pars.’ That’s when the trouble started.”

A bogey on 15 and a double on 16 allowed Suppa to shave the lead to two strokes going to the last two holes. They both birdied 17, but the heavy pressure mounted on Chin when Suppa drilled home a 12-foot birdie putt on the closing hole.

“Kyle hit a good putt,” Chin said. “Everyone was watching. I didn’t want to make a fool out of myself. A miss is possible; I didn’t want to go to a playoff.”

Suppa, a senior, closed with a 3-under 69 after his first-round 71.

“Bogeys on 13 and 14 put me a little too far behind,” Suppa said. “I was quite a ways back after that. I hit good shots on the last four holes, but the last hole was the only putt I made. I was hitting good putts — sometimes they go in and sometimes they don’t.”

Suppa’s birdie putt on No. 15 lipped out and he also missed chances for birdie on 16 and eagle on 17.

On the girls side, Punahou senior Mariel Galdiano won her third straight ILH championship to go along with her three state titles. She will go for her fourth state crown in May at Wailua Golf Course on Kauai, the site of her first hole-in-one.

Galdiano started the day with a five-shot lead over eventual runner-up and fellow Buffanblu senior Allisen Corpuz and wound up winning by two. She knew she had to be on top of her game to hold off Corpuz, who was the ILH champion as a freshman.

“I go into every round thinking that it’s a new start and it’s anyone’s game, so I still have to work hard and play my best,” she said. “It’s a huge honor (to win a third ILH title). Honestly, I never expected that to happen back then and to still be continuing to do as well even now. It means a lot and it’s especially going to mean a lot to me in the future looking back.”

At the finishing hole, Corpuz cut Galdiano’s four-shot lead in half with a 40-yard chip-in for eagle.

“I don’t think she (Allisen) knew it went in,” Galdiano said. “I saw it from where I was and I thought it was awesome, really. It’s shots like that that make golf interesting. It definitely made me think for a little bit. I was like, ‘Oh, I better go check it (the lead) again.’ ”

Despite that four-shot deficit, Corpuz didn’t give in, and she still has one more high school tournament to get to the top of the heap.

“States has always been my goal, so hopefully I can get it this year,” she said. “I was playing pretty well all day, but wasn’t really making any putts. I wasn’t really getting myself good birdie looks, but I kind of wanted to finish strong. (The chip) was a good shot. I knew it was going to be close and then Chloe (Wong, playing partner from ‘Iolani) goes, ‘Hey, you put it in the hole,’ so pretty exciting. Mariel has been playing really well for the last few years. It was playing pretty tough today, but she definitely put in a solid round and then (Monday) at OCC, she made some really good putts.”