Although Scottie Scheffler is all but guaranteed to win the Open Championship on Sunday, Rory McIlroy won the day in Round 3 at Royal Portrush.

With a legion of adoring fans following his every move Saturday, the Northern Irish golfer birdied three of his first four holes en route to a 5-under 66 that took him into fourth place. The highlight was a 56-foot eagle putt on the 12th, with a packed grandstand enjoying a perfect view from directly behind the 36-year-old.

"This could be one of the coolest moments I've ever had on the golf course," McIlroy said after the round. "The roar when this ball was in was insane. It was insane all day, but the noise after that putt went in was incredible."

The eagle was even more impressive because it came on the heels of McIlroy's lone bogey in the round - which resulted from arguably the strangest thing we've seen on the golf course this year.

After finding the rough off the tee, McIlroy struck his approach, only for an embedded ball inches in front of his own to fly into the air.

McIlroy admitted afterward that he was as puzzled as anyone when the ball popped up into the air.

"That is the most weird, ridiculous thing I've ever seen," he said. "Then my ball came out really weird and spinny. Yeah, just so strange."

He was able to add another birdie on the 15th after hitting the flag with his approach from the rough and will play in the second-to-last group Sunday.

McIlroy has posted some legendary come-from-behind wins on the PGA TOUR, but he gave an honest assessment of his chances in the season's final major.

"Scottie is the best player in the world right now. I think it's clear for everyone to see," McIlroy said. "He's just consistently so good each and every week he tees it up, so it's going to be a tall order to be able to catch him tomorrow. But I'm going to look forward to the challenge."