AP PHOTO - Zach Johnson, right, is congratulated by his caddie Brian Smith on the ninth green after the first round of the PGA Championship golf tournament Thursday at TPC Harding Park in San Francisco. Johnson, an Iowa native, is one stroke back of the leaders.

SAN FRANCISCO — By now, it is becoming all too familiar.

The starter stepped to the microphone and kept to the PGA Championship tradition afforded its champions. One player gets the longest introduction. “Now on the tee, the 1999, 2000, 2006 and 2007 PGA Champion … Tiger Woods.”

And then silence.

It’s the eerie product of golf amid a pandemic, and even after two months of no spectators, the quiet can be jarring.

Also familiar — Brooks Koepka bringing his best to the majors.

Jason Day and Brendon Todd wound up in a share of the lead Thursday after an opening round packed with action, just not cheers. Each posted a 5-under 65 at Harding Park, where fog gave way to the sun and the wind eased just enough to make the public course accessible to reasonable scoring.

The one constant appears to be Koepka.

Just two weeks after he missed a cut and was so frustrated he said he heaved a club 70 yards during practice, he powered his way to six birdies for a 66 that left him in a large group one shot behind.

“It’s only 18 holes right now,” Koepka said. “I feel good. I feel confident. I’m excited for the next three days. I think I can definitely play a lot better. Just need to tidy a few things up, and we’ll be there come Sunday on the back nine.”

Day, trying to emerge from a slump that has kept him from winning since 2018 and contending in majors since 2016, hit an approach to 6 feet for birdie on No. 9, the second-toughest hole on the course at 518 yards for a par 4 at sea level.

Todd’s round was equally impressive. Playing in the afternoon, as the wind strengthened, Todd made seven birdies and finished with a 10-foot par putt.

Koepka is the two-time defending champion, presented the opportunity this week to become only the seventh player in the 160-year history of major championship golf to win the same major three years in a row. It was last done 64 years ago.

He’s still a little annoyed that he missed a similar chance last year down the Pacific coast at Pebble Beach, when he finished runner-up in his bid for a third straight U.S. Open.

Koepka hasn’t won in more than a year. His left knee has been bothering him since last August. No matter. After a slow start, he quickly moved his way up the leaderboard and stayed there with a series of key putts for par — and one 12-footer for bogey — that gave him an ideal start to this major.

He was at 66 with eight other players, a list that included former major winners Justin Rose, Martin Kaymer and Zach Johnson, rising star Xander Schauffele and tour rookie Scottie Scheffler.

Johnson is one of three players who have played at every big event at Harding Park since it was refurbished.

The Cedar Rapids native was in his second year on the PGA Tour when he tied for 43rd in the American Express Championship, which Woods won in a playoff. He went 2-3, losing to Tim Clark in singles, at the 2009 Presidents Cup that the United States won. He went 2-1 in his matches at the Cadillac Match Play in 2015, but failed to advance to single elimination when Branden Grace won the group in a playoff.

And now he’s at the PGA Championship, with no complaints about the start, after opening with a 66.

Johnson played nine holes Monday in warm weather and thought he could handle the course. And then on Tuesday, when the chill and the fog and the wind took over, he thought it was one of the hardest golf courses he had ever played.

“But it was gettable today,” he said. “With minimal winds and obviously decent temperatures, this is what I remember this course playing the three other times I competed here. It’s a little longer, but this is how I remember it.”

Another Iowa native, Judd Gibb of Fort Dodge, shot a 7-over 77 in his first major. Gibb is a 1987 Fort Dodge Senior High graduate and former Fort Dodge Country Club professional.