As title defences go, it was the longest in US Women’s Amateur history.

That in ended in a gut-wrenching hook-out on a short par putt meant young Australian Gabi Ruffels had to cede the trophy to American prodigy Rose Zhang at Woodmont Country Club in Maryland.

That Ruffels reacted even more like a champion than when she won in dramatic fashion last year paints the complete picture.

“Rose was one of my toughest opponents … she just never let the door open,” Ruffels said with immense humility.

“She was dead straight down the middle and hits a lot of greens. Her wedge game is amazing and her putting is amazing.

“She's so solid. I can't believe she's only 17.”

Ruffels, while upset, was typically stoic and positive with what was a truly stunning achievement in winning 11 straight matches – over two years – to start her US Women’s Amateur career, the second most in tournament history and most in 110 years.

“This is the first time I've defended a tournament that I've won, so I wanted to see how I would deal with the pressure and expectations,” she said.

“I feel like I stayed mentally strong this week and can hold my head high with how I tried to go about my defence.”

Both women had their chances throughout the final, the second longest decider in the tournament’s storied history behind the 41 holes of 1966.

That neither could find more than a 2-up advantage at any stage of a nine-hour shootout was testament to the quality of their epic battle with the Victorian even par – concessions noted – when the end finally came.

Ruffels watched birdie chances slide agonisingly by on the 28th and 34th holes after she made one on the 31st to draw level with the 17-year-old.

Zhang, too, had opportunities go begging with a great roll just right on the 35th chief among them.

But the match will be remembered for the escape shot Zhang played on the final hole of regulation play.

Both women found the rough off the tee, but Ruffels’ error up the right of the long par-4 enabled her a shot at the green, even from deep rough.

Zhang, though, took a hybrid for her second to keep the ball under trees that grew ahead of her on the left side, meaning she couldn’t elevate over the thick rough between the trees and front left of the green.

With Ruffels into about 9m for birdie, Zhang then produced the miracle such an epic final demanded.

A low-ish punch first looked good, then landed front left and became fantastic as it trickled to within inches of the cup in a shot that might well be the best of her career; without doubt it will be the most timely shot she ever plays.

Her opponent’s par conceded, Ruffels then had another chance to finish the match with a birdie on the 36th, as she did last year in Mississippi.

The Victoria Golf Club member, though, left it short and overtime formalised when Zhang generously gave her the putt.

“That was tough, actually,” Ruffels said.

“I honestly couldn’t believe that she managed to stop that ball from that angle and that lie – I thought I was going to have two putts to win it all and then it was back to one in a hurry.

“In my head I was like, `Really?’. But that was just such an amazing shot and she did it all day. She’s a really good player.”

The Californian then had her own gilt-edged chance on the 37th, but rammed her birdie try past and had a knee-knocker back to extend.

After Ruffels played an exquisite flop shot that trickled to 1m on the 38th, Zhang’s birdie try to win it all again missed left and there was no inkling the match was about to end.

The Australian slightly blocked her par roll, but even then it didn’t appear to be missing when it dipped down on the right.

But then that fateful moment came as it slung around the back of the cup and came back up on the left side.

Match over.

“This is insane. I think everyone dreams big, but I try not get ahead of myself,” said Zhang, the world No.1-ranked junior.

“But now the trophy is in my hands, I really can’t believe it.

“The last two holes were a grind (and) Gabi rarely made mistakes today.

“I didn’t expect anything less from her, so I tried to play my own game and turns out everything went super well.”

For Ruffels, the next challenge comes quickly, flying to Scotland at the weekend for next week’s Women’s British Open.

“It’s tough to take right now, but it’s all a learning experience for me,” the University of Southern California junior said.

“But I’ll work through it all and get back up again. I can’t wait to play in Britain, so that will help … to play in a major championship.”