McIlroy maintains slender advantage at USPGA

Rory McIlroy will head into the final round of the USPGA Championship with a one-shot lead after an enthralling third round at Valhalla Golf Club

Rory McIlroy will head into the final round of the USPGA Championship with a one-shot lead after an enthralling third round at Valhalla Golf Club.

The Ulsterman carded a third-round 67 despite being far from his best to head into the final round on 13-under-par, one shot clear of unexpected challenger Bernd Wiesberger.

Rickie Fowler is a stroke further back on 11 under, Phil Mickelson birdied four of his final five holes to complete three rounds on 10 under and Jason Day birdied the last to sit alongside the left-hander three off the lead.

Henrik Stenson, Louis Oosthuizen, Mikko Ilonen and Ryan Palmer are still well in the tournament on 9 under.

It was a fantastic day at Valhalla, with a host of the world's best playing aggressive golf on a course offering up a number of birdies.

A number of early starters carded low scores - including Danny Willett and Brooks Koepka - setting the blueprint for the rest of the day.

Conditions were perfect for scoring and those in the chasing pack made a number of birdies over the early holes to apply some pressure to McIlroy.

It wasn't the most convincing start from the Ulsterman, who found water at the drivable par-4 4th, but a brave up and down paved the way for his first birdie of the day at the 5th.

Another followed at the 7th, but he gave it straight back at the 8th hole to reach the turn in one-under-par 34.

It wasn't long before he had company atop the leaderboard, though, with Rickie Fowler pouring in a long birdie putt at the 10th to reach 10 under.

McIlroy would also birdie the 10th, but a fluffed chip at the 12 led to a second bogey of the day. By that point, Bernd Wiesberger, playing some inspired golf in the company of Mickelson, had joined him atop the leaderboard.

Mickelson, meanwhile, bounced back from bogeys at 11 and 12 with three consecutive birdies from the 14th to reignite his championship.

But McIlroy, despite being slightly out of sorts, birdied the par-4 15th and stiffed his approach to the tough 16th to reach 12-under-par and join Wiesberger - who notched tap-in birdies at 17 and 18 - at the top of the leaderboard.

Mickelson also birdied the last to complete 54 holes in 10-under-par, one behind Rickie Fowler, who made an easy four in the group behind to finish the third round just two back.

But McIlroy showed his class at the end, birdieing the 18th to move one clear heading into a final round that promises to be one of the all-time USPGA Championship classics.