Final scores: -16 McIlroy; -15 Mickelson; -14 Fowler, Stenson; -12 Furyk, Palmer
-11 Els, Walker, Dubuisson, Mahan, Ilonen, Stricker; -10 Snedeker, Chappell
-9 Westwood, Schwartzel, Koepka, Warren, Scott, DeLaet, Wiesberger
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Image source, Getty ImagesRory McIlroy has won three events this year but only led going into the final day in one of them. On that occasion, his six-shot overnight lead at the Open Championship eventually ended up as a two-stroke advantage.
Clever boxing or signs of last-day jitters?
Dark skies hover ominously over Valhalla, before they pour a heap of rain over the players already out on the course. While the men further up the leaderboard go through their final drills, those who know they have next to no chance of winning are getting soaked. But the slinging rain is not stopping Vijay Singh, Thorbjorn Olesen and Ian Poulter sneaking up the leaderboard. The trio are each three under for the day.
Image source, Getty ImagesThe scoring average for the third round was 69.57 as players found birdies and maximised on the short par four fourth hole. The sub 70 mark is easily the lowest single round average in PGA Championship history.
Image source, ReutersEngland's Justin Rose (-4), the 2013 US Open champion, knows what it takes to win a major and he is backing Rickie Fowler and Jason Day to join the club.
"Fowler and Day are guys who are going to win majors. They've been knocking on the door for quite some time and they have to think their time will come soon," said the world number five.
Rose has just been welcomed on to the first tee by the announcer - his final round is up and running.
17:55: Marc Warren (Sco), Brooks Koepka (US)
18:15: Brandt Snedeker (US), Danny Willett (Eng)
18:45: Kevin Chappell (US), Lee Westwood (Eng)
19:15: Ryan Palmer (US), Jamie Donaldson (Wal)
19:35: Jason Day (Aus), Louis Oosthuizen (Rsa)
19:45: Rickie Fowler (US), Phil Mickelson (US)
19:55: Rory McIlroy (NI), Bernd Wiesberger (Aut)
But McIlroy dug deep, kept his card ticking over and nicked three birdies in the last four holes to grab a one-stroke lead over Austria's Bernd Wiesberger.
"I'm in the best position I can be in going into tomorrow," he said. "I would rather be the guy that's being chased and have that shot advantage than not."
Quite. McIlroy is out in the last pairing along with Wiesberger at 19:55 BST. Which reminds me - here are the most eye-catching tee times coming up...
It was hardly vintage McIlroy on day three though, which gives hope to the likes of Phil Mick et al.
A filthy hook from the tee on the driveable 292-yard fourth, a pair of dirty duffs around the eighth and 12th greens, plus an overhit approach shot on the 11th, were uncharacteristic errors by the in-form 25-year-old. And they brought smiles to the faces of Sunday golfers up and down the land.
Phil Mickelson, -10 and three behind 25-year-old Rory McIlroy, reckons he needs a 64 or lower to have a chance of pipping the young brigade to the title, with 28-year-old Bernd Wiesberger (-12) and Rickie Fowler, 25, a shot further back.
"I've been waiting for that seven, eight, nine under par round to come together," said Mickelson, 44.
"There are low scores out there tomorrow and I've got to get to seven, eight, nine to have a chance."
Image source, Getty ImagesThis is the current top of the pops going into the final round...
Image source, Getty ImagesBut, at the moment, it is advantage McIlroy. Wee Mac is a man who is used to that winning feeling, having clinched the Open and World Golf Championship in recent weeks. Who is going to be brave enough to wrestle the final major of 2014 from his grasp? Anyone?
Hello! And welcome to the final day of the US PGA at Valhalla, where Rory McIlroy (the world number one), Phil Mickelson (the experienced major winner), Jason Day and Rickie Fowler (the breakthrough hunters), plus Bernd Wiesberger (the little-known European) are the suspects looking most likely to lift the humongous Wanamaker Trophy, external on the 18th green. Where they will probably need a hand to lift that beast of silverware.
Image source, Getty ImagesThe world number one? Tick.
The experienced major winner? Tick.
The breakthrough hunters? Tick.
The little-known European? Tick.
All the usual characters have written themselves into the final-day plot of a major, but only one will top this leaderboard by the time we say goodnight. Expect more drama than a boxed set of Midsomer Murders over the next seven or so hours. Ready?