PORTRUSH, Northern Ireland -- The cheers grew louder and Shane Lowry kept getting better Saturday in the Open Championship.

The Irishman made two straight birdies around the turn at Royal Portrush to break out of a four-way tie, and Lowry later made three straight birdies to walk off the Dunluce Links with an 8-under 63 -- the 54-hole record (197) at the Open Championship.

He has a four-shot lead over Tommy Fleetwood.

With favorite son Rory McIlroy having failed to make the cut at Northern Ireland's first major since 1951, Lowry filled the void just fine.

He didn't mind the lack of attention, which instead was showered on the trio of Ulstermen -- McIlroy, Graeme McDowell and Darren Clarke at the start of the week.

"Those guys are from here; I grew up four hours away," said Lowry, who opened the tournament with 100-1 odds of winning at Caesars Sportsbook in Las Vegas. "I felt like I could come here and come under the radar. I'm not quite under the radar anymore. I didn't feel like a forgotten Irishman. But hopefully, I'm the one they're talking about tomorrow evening."

He was at 13-under 197, breaking by one the 54-hole record held by Tom Lehman at Royal Lytham & St. Annes in 1996.

Low scoring was helped by a day that ended in relative calm, perhaps ahead of the storm. The forecast for Sunday is so nasty that the R&A moved up the tee times by one hour in a bid to avoid the worst of heavy rain and gusts expected to top 35 mph.

There's also the chance of an internal storm brewing in Lowry.

This is the second time he has had a four-shot lead going into the final round of a major. The other time was in the 2016 U.S. Open at Oakmont. Lowry closed with a 76 as Dustin Johnson rallied for his only major.

The pressure for Lowry figures to be even greater this time around as he goes for a silver Claret Jug on the Emerald Isle.

The only golfer to blow multiple leads of four or more strokes after 54 holes of a major is Greg Norman.

Fleetwood did his part with a bogey-free 66, and he lost ground. He at least got into the final group as he goes for his first major.

"You have to look at it realistically," Fleetwood said. "I had a great day today. I had one of the best rounds of the day, and I was bogey-free. Shane just played great, and I'm four back. But that's it. I'm just happy with how I played."

J.B. Holmes, who started the third round tied with Lowry atop the leaderboard, tried to stay with him until he dropped two straight shots in the middle of the back nine. A birdie on the 18th gave him a 69, leaving him six back.

Still on the fringe of contention was a familiar face in the majors -- Brooks Koepka. He couldn't get enough putts to fall for the third straight day and still managed a 67, leaving him seven back.

"Nobody has hit it better than me this week," said Koepka, who posted his 11th round in the 60s at a major this year. "I've hit it as good as I could possibly imagine. I putted the worst in the entire field.

"It's been really bad. Very frustrating. Disappointed. But thankfully, [the wind is] going to blow tomorrow to have any sort of chance. I need to figure out the putter."

Justin Rose had a 68 and joined Koepka at 9-under 204, figuring that's just enough to at least stay in the conversation.

Behind him, Lowry, who teamed with McIlroy for Irish golf when they won the European Amateur Championship in 2007, kept widening the gap.

The pin was back right on the par-3 16th known as "Calamity Corner" because it drops off some 50 feet right off the green. He sent that tee shot onto the green and right at the flag until it settled about 10 feet away.

From the light rough to the left of the fairway on the 17th, Lowry hit a perfect chip-and-run to 3 feet for his final birdie. Holmes drove down the hill short of the green, close enough to use putter. He ran it about 8 feet by, and when it caught the lip and spun away, Holmes dropped the putter in disbelief.

Some of that surely was the frustration of seeing Lowry getting further and further away from him.

Lowry, who won the Abu Dhabi HSBC Championship on the European Tour earlier this year, can't think of a better day he's ever had on the golf course. His 63 was the 13th at The Open -- one stroke short of the major championship record that Branden Grace set at Royal Birkdale in 2017.

The support was more than he could have imagined.

"Every time I had a putt today," Lowry said, "I wanted to hole it so I could hear that roar."

The Associated Press contributed to this report.