AP photo by Peter Morrison / Rory McIlroy plays out of a bunker near the sixth green at Royal St. George's Golf Club during the first round British Open on Thursday in Sandwich, England.

SANDWICH, England — Jordan Spieth rolled in putts like it was 2017. Louis Oosthuizen put his runner-up finishes in the past two majors out of mind and soared to the top of the leaderboard.

They gave the opening round of the British Open a familiar feel Thursday, and things were back to normal on the wind-swept links at Royal St. George's Golf Club in other ways, too.

The roars and cheers of fans — with a daily capacity of 32,000, this is golf's biggest crowd since the coronavirus outbreak was declared a pandemic in March 2020 — rumbled around this quirky course off Sandwich Bay, just like old times. For Spieth, that was as welcome as being a British Open contender once again.

"It feels inside the ropes, from the first tee forward, the most normal of any tournament we have played thus far relative to that same tournament in previous years," the three-time major champion said.

His 5-under-par 65 certainly turned back time to four years ago, when he lifted the claret jug at Royal Birkdale — the last English venue to host the British Open — when he was hitting the ball better than he ever has.

The 27-year-old Texan was a shot off the lead held by Oosthuizen, who saved par from a fairway bunker on No. 18 for a 64 that tied Christy O'Connor Jr. in 1981 for the lowest opening round at Royal St. George's. That didn't look as though it would be the case after the 38-year-old South African opened with seven straight pars. He followed with six birdies in his next nine holes.

"I've learnt over the years playing major championships that patience is the key thing," said Oosthuizen, who won his lone major title in the 2010 British Open at St. Andrews in Scotland. He has six runner-up finishes in the majors since then, including at last month's U.S Open and at the PGA Championship in May.

Tied for second with Spieth was former University of Georgia standout Brian Harman, who made five birdies in his first eight holes.

Five golfers were knotted for fourth place at 66, and there was an even bigger jam one stroke further behind. The tie for 19th at 68 included Chattanooga native Keith Mitchell, an afternoon starter who made just one bogey. Fellow former Baylor School and Georgia golfer Harris English — one of the hottest players on the PGA Tour, he is second in the season-long FedEx Cup standings — was tied for 135th after a 75 with three birdies, six bogeys and a double on the 18th.

The top three on the leaderboard Thursday evening were among the morning starters who enjoyed the best of the conditions, notably soft bounces on the most undulating fairways and greens of the 10-course rotation for golf's oldest major. Yet many of the world's best couldn't take advantage.

Patience already might be wearing thin for U.S. Open champion Jon Rahm, who slapped his thigh in frustration after making a double bogey on No. 9, where he took two shots to get out of a pot bunker in the fairway. He shot a 71, the same as Bryson DeChambeau, who spent much of his first round up to his knees in deep grass — and cursing his driver, saying it "sucks" — after being unable to use his power to overwhelm the layout.

Shane Lowry, who won the 2019 tournament at Royal Portrush in Northern Ireland, also shot a 71. With last year's event canceled because of the pandemic, Lowry could finally be announced at a British Open as the reigning champion.

"It was a very special day for me," he said.

Not so for the majority of the afternoon starters, who encountered more prolonged gusts off the English Channel and slightly drier conditions.

Two months after winning the PGA Championship for his sixth major title, Phil Mickelson struggled to an 80, his highest opening score in any British Open. He was tied for last place in the 156-man field.

Benjamin Hebert and Webb Simpson, each with a 66, had the best scores among the afternoon starters. Top-ranked Dustin Johnson hit 14 greens in regulation after a round that spanned from late morning to early afternoon and said he was pleased with his 68.

Spieth had not won since his 2017 British Open triumph until he ended his slump at the Texas Open in April. He looked the happiest of anyone Thursday, saying he liked where his game was after matching his lowest score at any British Open. He also had a 65 on the first day of his win at Royal Birkdale.

He was glad there was a proper gallery to see it all at Royal St. George's.

"I feel like the fans here are very knowledgeable about the sport," Spieth said, "and they're also having a great time."