Following his US PGA Championship win, Rory McIlroy says that he has impressed himself with his golfing performance over the past few months.

Rory McIlroy seized the most satisfying major victory of his career Sunday at the PGA Championship, battling from behind against top rivals to put himself on an unimagined golf level.

McIlroy, three strokes down at the turn after leading by one after 54-holes, eagled the par-5 10th and added two clutch birdies to overtake Phil Mickelson and Rickie Fowler at rain-drenched Valhalla for his fourth major triumph.

'It is the most satisfying,' McIlroy said. 'To win it in this fashion and this style, it means a lot. It means that I know that I can do it, I know that I can come-from-behind. I know that I can mix it up with the best players in the world down the stretch in a major and come out on top.'

The 25-year-old from Northern Ireland fired a final-round 68 to finish 72 holes on 16-under par 268 to defeat US left hander Mickelson by a stroke with Fowler and Sweden's Henrik Stenson two adrift.

'It's great to have that in the memory bank and great to have in the locker going forward,' McIlroy said.

McIlroy, coming off a British Open triumph just three weeks ago at Hoylake, won his other major crowns at the 2011 US Open and 2012 PGA Championship, giving him four wins in the past 15 majors.

He has.