The fist pump on the 18th green told the story.

After under cooking his approach on the par-5 into a deep front bunker, Rory McIlroy splashed his third shot onto the putting surface and holed the birdie putt from eight feet. He pumped his fist knowing that it gave him not only a third round 67 but also a one-shot lead into the final round.

Rory McIlroy pumps his first after making a birdie on the 15th hole. PHOTO: Getty Images Rory McIlroy pumps his first after making a birdie on the 15th hole. PHOTO: Getty Images

McIlroy has won all three of his major titles with the 54-hole lead – he led by eight shots at the 2011 US. Open, three strokes at the 2012 PGA Championship, and last month it was a six-shot buffer at The Open Championship. He knew the importance of that final putt … to grab the lead by the barest of margins with 18 holes to play … advantage McIlroy.

“I look at the leaderboard, and the biggest thing I was concerned about on the back nine today was not being in the lead,” McIlroy said. “I got tied for the lead there for a while, and it didn't feel … I wanted to just get back in the lead.

“I knew Phil (Mickelson) was making a run. I knew Rickie (Fowler) was making a run.  I feel like I'm really confident right now no matter who is on that leaderboard; I feel like I have a pretty good chance in beating them.  As you said, one shot at a time, one hole at a time and just keep trying to do it like that, regardless of who is chasing me.

"It's a great position to be in," he added.

More rain swept across Kentucky and the Valhalla course throughout the morning of the third round, which left the Jack Nicklaus-redesigned layout exposed to a downpour of birdies. By days end, the scoreboard was a sea of red and Valhalla had produced the lowest scoring round average in PGA Championship history. Only four players in the top 40 could not break 70 in the third round.

McIlroy had a one-stroke lead over Jason Day and American Jim Furyk heading into the third round and there was a smattering of players within a few strokes. At one point during the third day the lead in the PGA was shared by six players as the big names pillaged the layout for birdies. With 18 holes to play there are a dozen players within five shots of McIlroy’s mark at 13 under and all have the pedigree to be considered genuine chances for victory.

Perhaps the only outsider will be McIlroy’s playing partner, Bernd Wiesberger, who surged up the leaderboard in the back of a flawless round of 65. With two birdies to his credit on the front nine, the Austrian added another at the par-4 12th and collected a trio of them from the 16th to the clubhouse.

“I've never played well in the Majors,” said Wiesberger, who has only made the cut once before in a major from five starts. “I've played well in the other bigger events in Europe and won a couple.  It's not the same, but you kind of get a feeling for what you have to do, how you have to handle yourself.

McIlroy explodes from the bunker short of the 18th green to set up a closing birdie and grab the 54-hole lead. PHOTO: Getty Images McIlroy explodes from the bunker short of the 18th green to set up a closing birdie and grab the 54-hole lead. PHOTO: Getty Images

“It's just on a different level.  But, you know, things are still the same.  You're still out there with your caddie trying to do the best you can.”

The 28-year-old freely confessed he doesn’t know what to expect.

“I've not been in contention in a major championship, so I don't know how it's going to turn out,” he said. “I'm just going to try to enjoy as I did today. I'm friends with Rory and I'm sure it's going to be a nice situation out there tomorrow again.

“Hopefully do the things well that I did today. Yeah, just enjoy myself.  From now on, it's just a bonus, really.”

Immediately behind Wiesberger are some big guns in Rickie Fowler (-11), Phil Mickelson (-10) and Jason Day (-10). Henrik Stenson (-9) and former Open Champion Louis Oosthuizen (-9) certainly can’t be discounted either.

“I feel like I'm in the best position I can be in going into tomorrow,” Rory said. “I would rather be the guy that's being chased and have that shot advantage than not.

“Of course it's different.  At Congressional, I had the eight-shot lead.  I think I had a three-shot lead going into Kiawah and then a six-shot lead going into Hoylake there.  You know, three shots isn't really that much, either, if you think about it and I was sort of able to pull away from the field there.

“Tomorrow standing on the first tee is going to feel different than how it felt a month ago at Hoylake, because you don't have that … it is going to be a shootout.

“You know the conditions are soft; guys are going to make birdies, and you know that you're going to have to make birdies, as well, to try and win.

Jason Day plays a remarkable recovery shot, barefoot, during the second round. PHOTO: Getty Images Jason Day plays a remarkable recovery shot, barefoot, during the second round. PHOTO: Getty Images

Australia’s chances of saluting a major champion in 2014 rest with Day, while Adam Scott remains a 50 to 1 shot as he will need to come from six shots back to secure the victory.

Day says he’s still feeling pretty good despite his interrupted preparation trying to get over the effects of vertigo.

“Obviously I'm trying to get back on my feet right now,” he said. “With all the frustrations, with injuries, withdrawing last week, it wasn't the greatest preparation coming to this event.

“I worked pretty hard over the last week, bar the vertigo, I'm in contention right now.

“Got one day left.  We'll see how it goes.  I'm still positive with how I'm playing. I feel like I'm playing pretty good golf.  I shot 65 yesterday, so it's definitely out there.

“Hopefully they set the course up reasonably well out there tomorrow. Hopefully we can go low.”

If Day goes on to win this championship he might look back at a miraculous par he made during the third round as a hole that helped him on his way.

After hooking his drive on the 2nd hole way left over a creek into dense, lush knee-high rough, Day had to take his shoes off to wade through the creek and play his second shot bare foot.

He extricated his ball to the right rough, wedged onto the green and holed the putt from 10 feet … easy as that.

“I was actually too lazy to get my shoes thrown over,” Day said.

“It was a great four there … a lucky four.”

Adam Scott gives the thumbs up to a fan after this third round 66. PHOTO: Getty Images Adam Scott gives the thumbs up to a fan after this third round 66. PHOTO: Getty Images

Scott, who carded a terrific bogey-free 66, said he’ll “have to go after” a low score to be any chance of overcoming McIlroy.

“Absolutely need to (go after it),” he said. “All my birdies today were from four feet and in.

“It's doable out there, if you can get it in the fairway enough. I still didn't get it in the fairway enough today.

“You have to firstly get it in the fairway to give yourself a chance to hit at pins.  If you do, then you can be aggressive.

“I would love to say I was not mis-hitting a shot, but sometimes it's even hard to go at pins when you are not 100 percent sure.  There's still plenty of trouble to get in out there.

“I'm probably too far back unless there's something special out there tomorrow.”

The leaders tee off just before 5am (AEST) with live coverage of the final round on FoxSports.

LEADERBOARD

1. Rory McIlroy (N.Ire)   66-67-67–200

2. Bernd Wiesberger (Aut)…69-68-65–201

3. Rickie Fowler (US)   69-66-67–202

T4. Phil Mickelson (US)   69-67-67–203

T4. Jason Day (Qld)   69-65-69–203

ALSO:

T13. Adam Scott (Qld)   71-69-66–206

T42. Geoff Ogilvy (Vic)   69-71-71–211

T42. Matt Jones (NSW)   68-71-72–211

T63. Marc Leishman (Vic)   71-71-72–142

* For the full leaderboard, click here