It's Jason's Day at the US PGA Championship

Jason Day claims his first major title
Jason Day claims his first major title

Australia's Jason Day won the US PGA Championship at Whistling Straits, with runner-up Jordan Spieth compensated for his near miss as he knocked Rory McIlroy off his perch as golf's world No.1.

Day fired a final round of 67 to become the first player to finish a major on 20 under par, beating the previous record of 19 under set by Tiger Woods in the 2000 Open at St Andrews, with his tears flowing as he enjoyed the crowning moment of his career.

"You guys saw on the 18th hole, even before I finished I had tears coming out of my eyes," said Day.

"I don't need to think about anything else now, it's such a special moment. I've just got to soak it in.

"I drove the ball so good and hit a lot of greens. I was patient in myself and disciplined. Everything mixed together it worked out perfectly.

"It's been a long journey. I didn't expect to ever grow up and be on the PGA Tour, it's an amazing feeling.

"I didn't expect I was going to cry. A lot of emotion has come out just because I've been close so many times and fallen short. To be able to play the way I did today in tough conditions with Jordan in the group. He was the favourite, to be able to play the way I did was amazing.

"Overall I'm just really pleased with how I played, I couldn't ask for anything better."

Spieth was looking to become only the third player after Woods and Ben Hogan to win three majors in a season, but a closing 68 meant he finished three shots behind and had to settle for overtaking Rory McIlroy to become the second youngest world number one behind Woods.

The 22-year-old also finished a remarkable 54 under par for the year's four majors, one better than Woods in 2000 when he won the US Open, Open Championship and US PGA.

Spieth has been aided to the top of the world rankings by McIlroy's ankle injury that forced him to miss a host of tournaments - including the British Open last month - but it is hard to argue that the American deserves his spot at the top of the rankings after a remarkable 2015.

"It feels really good. It's an unbelievable feeling," said Spieth.

"I knew walking up the 16th Jason was going to win so I was focusing on finishing second and accomplishing a career goal. So much work has gone into this and what a year it has been."

McIlroy admitted Spieth deserved to replace him at the top of the rankings, after he carded a closing round of 69 to finish nine under par and alone in 17th place.

"Honestly the way Jordan has been playing and the way I haven't played much this year - I think that was only my 12th or 13th event - it's very deservedly so," said McIlroy.

"Winning two majors, winning a couple of other times this year, had a chance at the Open, had a chance today. I'd be the first one to congratulate him because I know the golf you have to play to get to that spot, and it has been impressive this year."