In his opening round on Thursday, Koepka shot a two-under-par 69 that left him four strokes behind the leader, Justin Rose. When Koepka won at Shinnecock Hills last year, he opened with a five-over-par 75.

Pebble Beach’s spectacular seaside setting provided the stage for one of the sport’s most indelible performances: Woods’s 15-stroke victory in the 2000 U.S. Open. Trevor Scott, a spectator at Pebble, said that he watched Woods lap the field then and that he felt the same slack-jawed awe Tuesday when he braved wilting heat to watch Koepka play nine holes ahead of the tournament’s 119th edition.

“This guy,” Scott said, “is a straight-out athlete.”

The comparisons to Woods don’t end there.

“Tiger just went to a different place mentally than the rest of us can go to,” said Graeme McDowell, who won the U.S. Open in 2010, the last time it was held in Pebble Beach. “But Brooks can get himself there with the little chips, the little comments, and take himself to places we’ve only seen from guys like Tiger.”

Though Koepka doesn’t go out of his way to promote himself, fame has managed to find him. He had to change his phone number this week because fans had somehow gotten ahold of it and were bombarding him with text messages and voice mail messages.

Asked about their contents, Koepka blushed and said, “I don’t know if I can say.”

Koepka is not flashy, but his galleries are growing ever more colorful. Standing next to Scott in a line for autographs on Tuesday was Patrick Shaw, who cried out to Koepka that he had completed 50 push-ups in the morning “so I’d look buff like you.”