He has been in this position several times before, but he hasn't won two majors in one season like he has a chance to on Sunday.
Third-round leader Rory McIlroy has won his last two starts, including his third major when he beat Sergio Garcia and Rickie Fowler by two at the Open Championship. McIlroy did the same to Garcia a week ago at the WGC-Bridgestone Invitational.
Unlike last year's 54-hole leader, Jim Furyk, McIlroy has been rock solid with the third-round lead. Between his time on the European and PGA Tours, McIlroy has won six of the 10 times he had the 54-hole lead before this weekend.
The 25-year-old was the 54-hole leader four times in majors and he won three of those four, including his last three in a row. Since the PGA Championship became a stroke-play event, 31 of the 56 third-round leaders have gone on to win the title. McIlroy was the last to do so in 2012.
As good as McIlroy has been recently with the 54-hole lead, he has plenty of company right behind him on the leaderboard.
Bernd Wiesberger, Rickie Fowler, Phil Mickelson and Jason Day are all within three strokes of McIlroy's lead. In all, there are 11 players within five of the Ulsterman.
"Tomorrow standing on the first tee is going to feel different than how it felt a month ago at Hoylake, because ... it is going to be a shootout," said McIlroy. "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."
If McIlroy can 1-putt nine of the last 12 greens like he did in Saturday's third round, he'll be tough to beat.
Here is a look at how recent PGA Championships have been won.
DUFNER RALLIES TO WIN FIRST MAJOR (2013)
Jason Dufner may have stumbled on the final two holes, but he did more than enough over the first 16 to win the 95th PGA Championship.
Dufner had four birdies and 12 pars in the first 16 holes en route to a closing 2-under 68. He ended his first major championship victory at 10-under- par 270 at Oak Hill.
Dufner had coughed up the lead late in the 2011 PGA Championship, then lost to Keegan Bradley in a playoff. But his stellar iron play in this final round wouldn't allow that to happen.
Furyk stumbled to a 1-over 71 to end alone in second at minus-8. The 2003 U.S. Open champion failed to hold the 54-hole lead for a fifth straight time in which he was in that position.
Dufner looked as solid as an oak on the front nine as he carded six pars to go with three birdies, none of which were from more than five feet out. He remained solid until dropped shots on the final two holes. He was two clear before those dropped shots, and remained there as his playing partner, Furyk, tripped to bogeys on those two holes as well.
RORY ROMPS TO TITLE (2012)
McIlroy cruised to his second major title when he won in historic fashion at The Ocean Course at Kiawah Island.
He shot a 6-under 66 and won by eight strokes to establish a new tournament record for largest margin of victory and eclipsed the great Jack Nicklaus, who won the PGA by seven shots in 1980.
"It's a nice record to have. I don't care if I win by one, or by eight," said McIlroy. "It's a nice achievement."
McIlroy finished at 13-under 275.
The victory propelled McIlroy back to No. 1 in the world rankings.
FIVE DOWN WITH THREE TO PLAY (2011)
Bradley erased a 5-shot deficit with three holes to play to force a playoff with Dufner.
The two headed to a 3-hole playoff at Atlanta Athletic Club and Bradley made a 4-foot birdie putt at the first extra hole. Dufner 3-putted the second hole for a bogey and Bradley was two clear on the last playoff hole.
Dufner made a 20-foot birdie putt to make things interesting, but Bradley calmly 2-putted for par, the 1-shot victory and the Wanamaker Trophy.
"I can't believe this thing is sitting next to me," Bradley said.
Bradley became the third player in golf history to win in his major championship debut. Francis Ouimet won the 1913 U.S. Open in his first major appearance and Ben Curtis did the same at the 2003 British Open.
WAS IT A BUNKER OR NOT? (2010)
Martin Kaymer became the first German to win the PGA Championship in a 3- hole playoff over Bubba Watson, but the story of the tournament surrounded Dustin Johnson, who was denied a trip into the extra session after grounding his club in a bunker on the 72nd hole.
Johnson had a 1-shot lead with one hole to play in regulation, but a bogey apparently sent him toward a playoff. Afterward, it was ruled that his second shot was in a small bunker, unbeknownst to Johnson. He was assessed a 2-shot penalty for his grounding of the club and dropped into a share of fifth.
"Never once did it cross my mind it was a sand trap," Johnson said at the time.
The 3-hole playoff began with Watson's birdie at the 10th to take a 1-shot lead, but Kaymer responded with a 12-foot birdie putt at the 17th to tie it with one hole to play.
The pair returned to the 18th, where both players teed off into the rough. Watson appeared to have the better lie and tried to go for the flag, but it didn't work and his ball landed in a stream well short of the green.
Kaymer elected to pitch out with his second after his opponent's watery mistake. He hit his third 15 feet right of the hole.
After Watson took his penalty drop, he knocked his fourth over the green into a bunker. He blasted out and his ball hit the flagstick, but rolled three feet away.
Kaymer needed two putts for the win and he ran his par putt about two feet past the cup. Watson kicked in his short double-bogey putt and Kaymer studied his little winning putt.
Kaymer tapped in for the bogey and the win.
"It feels great," Kaymer said. "I get goose bumps just talking about it. It's fantastic."
TIGER FINALLY TOPPLED (2009)
The 2009 PGA Championship had presumably ended after Saturday's third round.
Tiger Woods held a 2-shot lead after 54 holes, and never surrendered such an advantage in a major tournament throughout his career. In 14 previous occurrences, Woods went on to capture whatever title he was chasing.
Not this time.
Y.E. Yang battled Woods all day, taking advantage of the top player's poor putting to claim his first major championship.
The two were tied at 6-under par when they reached the drivable, par-4 14th. Woods drove into a bunker and Yang came up just short of the putting surface. Woods blasted out to seven feet, but Yang chipped in for an eagle to move in front by himself.
Woods rolled in his birdie effort and trailed by a stroke.
The difference remained heading to the 18th, and both drove into the fairway at the par-4 final hole. Yang hit a 3-hybrid that was headed directly at the hole. When it stopped, Yang had eight feet for birdie.
The pressure was on Woods and he pulled his second into the left rough. He needed to chip-in to have any chance to force a playoff, but his shot from the tall grass rolled past the hole some 10 feet.
Yang ran home his birdie putt and the 37-year-old from Seoul raised his arms and screamed in excitement. In the early hours of Monday morning, his Korean fans watched their countryman make history.
A WIN FOR EUROPE (2008)
No European had won the season's last major since 1930, but Padraig Harrington ended the drought for an entire continent by erasing a 3-shot final round deficit to win his second consecutive major championship.
It was more heartbreak for another European, Garcia, who has yet to finish a major atop the leaderboard.
Garcia held the lead on the back nine, but Harrington, who had beaten Garcia in a playoff at the 2007 British Open, made several crucial putts down the stretch to overtake him, including a 12-foot par save on the 18th to win it.
Harrington vaulted into a share of the lead with birdies at 10, 12 and 13, but bogeyed the 14th to give the lead back to Garcia and American third-round leader Ben Curtis.
Harrington saved par at the 16th, while Garcia and Curtis both fell backwards with bogeys to create a 3-way tie with two holes to play.
At the par-3 17th, Harrington hit his tee shot to seven feet, while Garcia landed closer. After Harrington stepped up and drained the birdie effort, Garcia's old nemesis resurfaced, missing from five feet away.
Harrington walked to 18 with a 1-shot lead over Garcia, while Curtis had bogeyed the 17th to take himself out of contention.
Harrington drove into a bunker and hit a terrible layup into the rough at the difficult closing hole at Oakland Hills.
Garcia drove into the rough and hit his second into a greenside bunker. Harrington, easily becoming one of the toughest closers in golf, knocked a 7-iron to 12 feet for his third.
Garcia blasted out to 10 feet and if Harrington missed his par putt, Garcia would need that 10-footer to force a playoff.
Harrington never gave him a chance.
TIGER GOES BACK-TO-BACK, AGAIN (2007)
Woods improved to 13-0 with a 54-hole lead at major championships, closing with a 1-under 69 to win his fourth PGA Championship by two strokes over Woody Austin.
Woods led by as many as five strokes on the final day, but a bogey at the 14th saw his advantage trimmed to one after Austin's third consecutive birdie at the 13th.
The master of closers, however, responded with a birdie on the 15th and parred the remaining three holes to win the title.
It was Woods' fifth title of the year and 59th overall, as the world's best player continued his domination of golf. It was his 10th top-5 finish in the last 12 majors contested.
ANOTHER WIN FOR TIGER AT MEDINAH (2006)
With his second PGA Championship victory at Medinah Country Club, Woods captured his 12th major, moving him into second all time on golf's most prestigious list.
At age 30, the question was more "When?" than "If?" Woods would surpass Jack Nicklaus' 18 major titles.
Things look different now.
Woods, at 18-under 270, matched his own PGA Championship record for lowest score in relation to par, which he originally set in 2000 along with Bob May.
He became the only player to win a PGA Championship on the same course twice after winning there in 1999 as well. It was his second straight year with two major titles and third time in five years.
For the top player in the world, it was simply another bushel of records to collect.
WIRE-TO-WIRE FOR PHIL (2005)
Even Woods knew that Mickelson would go on to victory.
Rain forced play into Monday for the first time since 1986, with Woods as the clubhouse leader, but Mickelson was the leader with four holes to play. Instead of remaining in New Jersey to see the outcome, Woods traveled back to Florida on Sunday night and was heavily criticized.
It proved to be the right decision, however, as Mickelson got up-and-down from 50 feet away for a closing 2-foot birdie to win by one stroke over Thomas Bjorn and Steve Elkington. Woods finished tied for fourth, two strokes back.
After ending an 0-for-46 drought in majors at the 2004 Masters, Mickelson needed only seven more tries for his second title.
Mickelson became the seventh wire-to-wire winner at the PGA Championship and the first since Woods in 2000.