Pebble Beach again looked vulnerable to unusually low scoring as Justin Rose attempted to extend his lead on day two of the 119th US Open.
Rose birdied his final three holes on Thursday evening to card an opening six-under-par 65, equalling the lowest round in a US Open at Pebble Beach set by playing partner Tiger Woods on his way to a record 15-shot win in 2000.
And that was not the only significant statistic on day one as a lack of wind and soft greens helped the field post a scoring average of 72.66, almost two strokes better than the previous best on the Monterey Peninsula course of 74.51 in 1992.
A total of 39 players broke par on the opening day, just five fewer than the tournament record of 44 set at Erin Hills two years ago, while the 17 eagles recorded surpassed the single-day mark of 13 from the first round in 1983 at Oakmont.
Rose was among the early starters greeted by damp, overcast conditions on Friday and after starting on the back nine, he followed five straight pars with a birdie from six feet on the 15th.
That took the 2013 champion to seven under par and two ahead of Chesson Hadley and Matt Kuchar, with Rickie Fowler, Xander Schauffele and Louis Oosthuizen also five under but among the later starters.
Hadley had covered the back nine in 34 despite a double bogey on the 15th, while Kuchar had birdied the first, fourth and seventh.
Defending champion Brooks Koepka, who is seeking a third straight US Open title, was two shots further back after playing his first seven holes of the day in one under.
Woods, who single-putted 11 greens in an opening round of 70, was a shot further back after managing just one birdie from a number of good chances in his first six holes.