Noh, chasing a second career PGA Tour title to go with his 2014 Zurich Classic of New Orleans win, eagled all three of the par-fives on the Tahoe Mountain Club course, especially valuable under the Modified Stableford scoring system that awards points for birdies and eagles and subtracts them for bogeys and worse.

Noh also had five birdies and a pair of bogeys, his 23 points putting him six clear of American Beau Hossler, whose two eagles included an ace at the par-three third hole.

Noh said he'd never had three eagles in a PGA Tour round before, and it wasn't the kind of outing he was expecting with the course firming up and winds rising in the afternoon.

"It's just so much fun to play today," said Noh, who earned five points for each eagle.

While some players find the points system an invitation to be more aggressive, Noh said he tried to use his usual approach.

"Nothing changed... Every hole, every single shot. It's just a better result today," he said, noting that he hit three greens on the three par-fives and had one tap-in eagle and one eagle putt of more than 30 feet.

"I putted pretty good today," said Noh, who also had an eagle putt of more than 15 feet.

Hossler had set an early target at 17 points in pursuit of his first PGA Tour title.

He eagled the par-five sixth to go along with his hole in one at the third.

"I was kind of in between clubs," Hossler said of the ace. "I think it was like 211 (yards), but at altitude it’s playing like 190.

"I hit seven-iron and it landed in a good spot and it went in."

His only regret - he couldn't enjoy the highlight footage.

"It looked like it was the only hole on Tour this year that had no camera," Hossler said.

France's Alexander Levy had eight birdies without a bogey and was joined on 16 points by American Ryan Gerard - who had nine birdies and two bogeys.

Carson Young, Patrick Rodgers and Germany's Maximilian Kieffer shared fifth on 15 points.

The tournament is played opposite the Open Championship at Hoylake.