Rory McIlroy produced the back nine of his career to clinch back-to-back majors with a one-shot  victory over Phil Mickelson at the PGA Championship.

The 25-year-old becomes the fourth youngest player to win four majors – adding to his Open, US Open and 2012 PGA Championship titles.

It looked to be slipping away as the World No.1 lost his over night lead with dropped shots at 5 and 6 on a rain soaked Valhalla.

McIlroy and playing partner Bernd Wiesberger were often waiting up to 10 minutes to play their shots after a long rain delay clogged up the field.

Rickie Fowler, Phil Mickelson and Henrik Stenson surged to the front but McIlroy kept his patience and was rewarded with a superb display on the home straight.

A birdie at seven was followed by an eagle at 10 before birdies at 13, 17 put him back in charge.

Under the most intense pressure, with three top players breathing down his neck, McIlroy stood up to the test and was more than a worthy champion.
I didn’t think in my wildest dreams I’d have a summer like this" There was a steely look in his eye when he punched the air on 13 and as Stenson and Fowler bogeyed 14, then Mickelson dropped a shot on 16, the momentum had swung back in favour of the Northern Irishman.

McIlroy reached the 18th on -16 with Stenson in the clubhouse on -14, Mickelson and Fowler on the same score up the last fairway.

Mickelson made birdie and Fowler just a par allowing McIlroy to pitch out of a bunker and two putt his way to a one-shot victory.

With the light fading, McIlroy was embraced on the 18th green by his father Gerry and the Rodman Wannamaker trophy was his for a second time. 

“I didn’t think in my wildest dreams I’d have a summer like this,” McIlroy said. 

“I’ve played the golf of my life. I showed a lot of guts out there to get the job done.”

Rory paid tribute to Rickie Fowler and Phil Mickelson for helping him finish the job on Sunday night.

“I suggested that we play up as a four,” McIlroy added.  

“I didn’t know if they wanted to do that or not. You know, to get this thing finished and get this thing over and done with; and the guys let us play up with our drives, and they didn’t need to do that, they could have just left us on the tee box there and just play normally, but they showed a lot of class and a lot of sportsmanship by doing that.  

“I thanked Rickie and Phil in the scorer’s area and reiterated what I said in my speech out there on the 18th green. 

“It was a classy move by them, and if they had not of done that, we might not have been able to get it all done because it was getting really dark out there.”