Jason Day claimed his first Major Championship in record breaking fashion as he finished three shots ahead of Jordan Spieth to win the US PGA Championship at Whistling Straits.
The Australian carded a closing 67 to finish the tournament 20 under par, the first man ever to do so in a Major, as he held off a chasing pack of Spieth, Branden Grace and Justin Rose.
Day had shared the lead at both the US Open Championship and the Open Championship after 54 holes but got over the line in Wisconsin after six top tens in his last 11 Major appearances.
Spieth, who became World Number One following his second placed finish, was aiming to become just the third man in history to win three Majors in a year following his victories at the Masters Tournament and US Open but it was Day who was destined to make history on the shores of Lake Michigan as he surpassed Tiger Woods' 19 under total at the 2000 Open Championship.
Day was in tears on the 18th green before he had even holed out and admitted he did not expect the occasion to get to him as it did.
"It's been a long journey, I didn't expect to ever grow up beyond the PGA Tour," he said. "I'm being all emotional here but it's an amazing feeling.
"The work that I've put into my game ever since I was a 12 year old kid and to be able to stand in front of a crowd like this today and win the PGA Championship is pretty special. Jason Day
"I didn't expect I was going to cry, a lot of emotion has come out just because I have been so close so many times in Major Championships and just fallen short, just really close.
"And to be able to play the way I did today, especially in tough conditions, especially with Jordan in my group, I could tell that he was the favourite and just to be able to pay the way I did and finish the way I did was amazing."
A bogey from Spieth on the fourth briefly reopened Day's three shot advantage but Grace nailed a 35 footer on the fifth to leapfrog the American into second at 14 under.
Grace followed that with a birdie on the sixth and Rose, who had parred his first four holes, also picked up shots on the fifth and sixth.
Day found the bunker off the fifth tee but still managed to make birdie, as did Spieth, and the top four were threatening to pull away from the rest of the field despite Anirban Lahiri reaching the turn in 32.
The scorching pace of scoring continued as Grace made a 17 foot putt for a third consecutive gain but back on the sixth both Day and Spieth picked up further shots, the latter getting up and down from some thick rough.
Everything Day touched seemed to be finding the hole and he drained a spectacular 50 footer on the seventh to make it three birdies in a row himself and move three clear of Grace at 19 under.
The Australian found a fairway bunker on the eighth and gave a shot back but saved par on the ninth after a poor second while Spieth dropped a shot after finding the rough.
Ahead of them, Grace also found rough off the tee and, after failing to get his third shot on the green, gave two back as Rose put his second inside six feet for birdie.
The Englishman picked up another birdie on the 11th to get within two shots of the leader but Day extended his advantage back to three on the same hole after Spieth had gained on the tenth.
All of the leading four parred the 12th but Rose doubled bogeyed the 13th after getting in bunker trouble down the left while Grace picked up a birdie and Day now had a four shot lead with six to play.
Spieth birdied the 13th and made a remarkable par save on the next but Day became only the second player to ever reach 20 under in a Major with a birdie and a bogey for Grace on the 15th effectively turned it into a two horse race.
Day found sand off the tee on the 15th and his lead was cut to three but the pair then matched each other home.
"There were plenty of times when I got out of it, more so just thinking about the future, especially on the back side there were a few times where I had to pull myself back in and say it's not over, you've got to keep grinding, keep fighting," Day added.
"And once I did that I kind of pulled myself back and started hitting the quality shots that I needed to.
"Just to be able to finish with a birdie on 16 and two pars on 17 and 18 felt fantastic."
Grace finished two shots behind Spieth on 15 under with Rose a further shot back and Brooks Koepka and Lahiri on 13 under.
