Australia's Jason Day held his nerve to end five years of close calls at the majors with an emotional breakthrough victory by three shots over American Jordan Spieth at the PGA Championship.

World number five Day, two ahead of Spieth overnight, never relinquished his lead as he closed with a five-under-par 67 on a blustery afternoon of hazy sunshine at Whistling Straits to post a major record low of 20-under 268.

The previous best at a major was the 19-under 269 by Tiger Woods when he triumphed by eight shots in the 2000 British Open at St. Andrews.

Day fended off the challenge of Spieth, who had been bidding for a rare third major victory in the same year, with four birdies in the first seven holes, followed by three more after the turn.

Last 10 PGA Championship winners
2015 Jason Day  
2014 Rory McIlroy 
2013 Jason Dufner 
2012 Rory McIlroy 
2011 Keegan Bradley 
2010 Martin Kaymer 
2009 Yang Yong-eun 
2008 Padraig Harrington
2007 Tiger Woods 
2006 Tiger Woods

The 27-year-old Australian, who had previously recorded nine top-10 finishes in the majors - six of them in the top four - had to wipe tears from his eyes before he tapped in a one-foot putt for par on the 18th green.

Spieth, the Masters and US Open champion, had to settle for second after closing with a 68 and securing the number one ranking for the first time, at the expense of Rory McIlroy.

Day, who was embraced by his pregnant wife Ellie as he made his way off the green, became the fifth Australian to win the PGA Championship after Steve Elkington (1995), Wayne Grady (1990), David Graham (1979) and Jim Ferrier (1947).

"It's an amazing feeling," a visibly emotional Day told CBS Sports after being presented with the coveted Wanamaker Trophy, which he hoisted high in celebration.

"Winning the PGA Championship is very special. I felt no one was going to stop me today. I played fantastic, through the whole round. Even though I made a couple of mistakes, I really felt good about my game.

"Just to be able to finish with a birdie on 16 and two pars on 17 and 18 felt fantastic. I never expected to be here. I can't say anything else because I'm going to cry."

South African Branden Grace, who pulled within a shot of Day's lead after making four birdies in five holes from the third, signed off with a 69 to place third at 15 under.

Championship scores (top 5):

-20 Jason Day (Australia) 
-17 Jordan Spieth (U.S.)
-15 Branden Grace (South Africa) 
-14 Justin Rose (Britain)  
-13 Anirban Lahiri (India)  
      Brooks Koepka (U.S.)

Source: Reuters