An emotional US captain Jay Haas wept with joy as he watched his son Bill close out the final singles match on the last green to win the 11th Presidents Cup on Sunday.

"I don't know if I'm going to get through this. I can't," he said, voice cracking as tears welled in his eyes alongside the 18th green at the Jack Nicklaus Golf Club in Incheon, South Korea.

– Presidents Cup: USA beat Internationals

Moments earlier Haas junior, only in the team after being given a captain's pick by his father, had beaten local hero Bae Sang-Moon to secure a 15.5-14.5 victory against the International team.

"Before Bill played 17, I said, 'Come on, Bill, win one for your mom here. Your mom deserves this'. 

"Oh, my gosh," he said as more tears fell. 

"When we put him out 12th, (we) had no idea obviously that was going to happen. But he played beautiful down the stretch. Couldn't even have dreamt this. I'm just real happy for the guys."

This was such a fun way to end an incredible week! #TeamUSA #PresidentsCup pic.twitter.com/hVno9zfEl6

— Bill Haas (@BHaasGolf) October 11, 2015

Bae had a chance to grab a share of the trophy but fluffed a chip with his third shot. When he couldn't hole his next attempt the handshakes followed and the US had secured their sixth Presidents Cup in a row and ninth outright in the most dramatic circumstances.

Jay Haas regained his composure later and told a news conference alongside his winning players what had been going through his mind.

"I believe I would have been just as nervous no matter who was out there, but I was more emotional because it was Bill. 

"We had a lot of red up on the board early. Then all of a sudden, some of the matches turned a little bit different. And I thought, 'Bill's match is probably going to matter'.

"I was much more emotional than if it would have been anyone else on the team, but no less proud. They all are fantastic, I just can't say enough. I feel like, except for maybe Phil, they are all like my sons," added Haas to laughter, refering to Phil Mickelson, the oldest player in the team at 45.

Bill Haas said it was the most nerves he had ever felt in his 11 years as a professional.

"Those holes down the stretch were very difficult. I can't even imagine these Major winners up here, what they are feeling like down the stretch, having felt that," he said.

Bill Haas had realised midway through the back nine that it might all come down to his match, and he said it had been a scary thought.

"When I was on 13, I looked over at the scoreboard and I saw we were maybe up in two, down in two, all square in one. And I knew right then.

I was like, man, it's definitely on — all of a sudden it's on me."

He revealed that some words from British Open champion and US team mate Zach Johnson had inspired him. 

Haas told Johnson on Saturday night after being drawn last out: "Man, I hope you guys go out and take care of business before it comes down to me."

But Johnson was having none of it and told Haas to be positive. 

"He goes, 'You want that. That's what you want. You want to be in that position and you should go get it'," said Haas.

"It feels really amazing now the way it all worked out. It was a very great moment for me and my dad."