Rory McIlroy leads by a stroke entering final day of PGA Championship; Phil Mickelson in running

To borrow a phrase from local terminology, here in the shadow of Churchill Downs, they're at the post. Considering the way Saturday went at the PGA Championship, there is no way to look at the final round Sunday other than say it is going to be a horse race.

For the first time this season, one of golf's major championships is filled with excitement and the leader board is filled with the game's thoroughbreds as it heads down the stretch. Rory McIlroy still is leading, but only by one stroke, not three or more as he has in his three major titles. He is at 13 under par, coming off a 4-under 67 on a spirited, birdie-bedecked day when Bernd Wiesberger of Austria shot 65 to go 12 under.

They will be in the final group, but only a nose ahead of Rickie Fowler (11 under) and Phil Mickelson and Jason Day (each 10 under), and some accomplished and / or promising players bunched behind them. Rain had softened the greens at Valhalla Golf Club, allowing golfers to shoot directly at flags. Wiesberger nearly holed out an 8-iron and had a tap-in birdie on No. 17 to briefly take the lead, only to have McIlroy draw even with a birdie on No. 15 seconds later.

At one point, five players shared the lead at 10 under and five more were at 9 under. Fans whooped as they do at the Kentucky Derby and the golfers figured there will be more of the same today.

"It is going to be a shootout," McIlroy said. "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."

The day brought out the best in Wiesberger, the least known of the contenders -- at least in the United States.

"Well, given a population of just over 8 million people, we have around 100,000 golfers in the clubs," he said. "So I would reckon about 90,000 would be [watching] the TV by now. At least I hope so."

Before this week, his aggregate score in major championships was 42 over.

"I've played well in other big events in Europe and won a couple," he said. "It's not the same, but you kind of get a feeling for what you have to do, how you have to handle yourself."

He expects a relaxed round today with McIlroy, a laid-back type, whom he knows from the European Tour. McIlroy did not get flustered Saturday, even though he acknowledged that he did not have his best game. He knew that he needed only 24 putts, including a key par on the short par-four fourth, after having taken a penalty stroke for a lost tee shot.

"To get it up and down out of that drop zone was really important," he said.

If nothing else, it countered the momentum Day, his playing partner, had built with a remarkable par save in his bare feet beside a creek on No. 2.

There is no question among the rest of the field that McIlroy, coming off a British Open win and a victory in the WGC-Bridgestone Invitational, will be tough.

"He's not going to back up. If someone is going to beat him, they are going to earn it," said Fowler, who will be in the penultimate group with his buddy Mickelson this time after having been in the last group in each of the past two majors.

McIlroy said: "I feel like I'm in the best position I can be in. I would rather be the guy that's being chased and have that shot advantage than not."

Still, judging by the way the field played Saturday, a photo finish is not out of the question.