Like Pádraig Harrington and Paul McGinley a few years ago, Tiger Woods reckons Rory McIlroy is just like Phil Mickelson - up one minute and down the next.
The 14-time major winner finished near the back fo the field on six over after a closing 75, putting US Ryder Cup skipper under more pressure.
But when asked about McIlroy, Woods said: “The way he plays is pretty aggressive. When he gets it going, he gets it going.
“When it gets going bad, it gets going real bad. It's one or the other. If you look at his results, he's kind of that way. Very similar to what Phil does.
“He has his hot weeks and he has his weeks where he's off. And that's just the nature of how he plays the game."
We're not so sure that's going to apply for much long but It was interesting to hear Woods, normally so complimentary, suggest that McIlroy was something of a poor, or at least streaky, putter.
“If he drives it like he is right now and he's making the putts again, that's something that's been missing a little bit," he said. “He hasn't really made the amount of putts that he did a couple of years ago.
“But now he's starting to make those 10 to 15-footers. That turns rounds around. You make two or three birdies in a row, you make a par putt here and there.
“Next thing you know a round you would normally shoot 1- or 2-over, and all of a sudden it's 69. And then you get the hot round and it's 66 or 65.”
Shane: Rory’s "A" game is unbeatable
Shane Lowry believes Rory McIlroy is so good it’s “scary”.
Tied ninth, his best finish in a major, Lowry said: “I think his ‘A’ game right now is pretty much almost unbeatable, it's pretty scary how good he is.
“He's only 25 but he's been an unbelievable talent since he was a kid. Anything he does you're not surprised to see it.
“I can't remember much as amateurs. But the one thing that stands out in my mind is how good he played when I played a practice round with him at Congressional.
“And that's why I think his good golf — his best golf — is almost unbeatable.”
Watson: The light went on for Rory
US legend Tom Watson believes Rory McIlroy learned from his failures to become Open champion.
The five-time Open winner said: “He’s gone through a struggle with his golf game over a period of time. And now it seems like he's got it back. And you learn a lot from your failures.
“I know it was a burden on him. The frustration was there with him. All golfers feel the same frustration.
“You've gone through the times where you couldn't break egg, and yet we still try.
“That's what the game does to you. And then finally all of a sudden the light switch will turn on, something will make a change in your golf swing, and it gets easy.
“That's what happened to me many times in my career, and it seems like it's happened to Rory.”