Justin Rose remained the man to catch as he tried to take another step towards a second US Open title on day two at Pebble Beach.
Rose, who won at Merion in 2013, birdied his final three holes on Thursday to card a 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.
For the second day running Rose also birdied the 18th by getting up and down from a greenside bunker, only to bogey the innocuous par-four first after missing the fairway despite taking an iron off the tee.
The 38-year-old bounced back in ideal fashion with a birdie from close range on the next but dropped his second shot of the day on the fourth following a wayward drive into a hazard.
At seven under par Rose enjoyed a two-shot lead over American Aaron Wise, who had set the early clubhouse target after adding a second round of 71 to his opening 66, with late starters Rickie Fowler, Xander Schauffele and Louis Oosthuizen also five under.
Open champion Francesco Molinari was on four under par with four holes to play, while defending champion Brooks Koepka, who is seeking a third straight US Open title, was two shots further back alongside Woods and Jordan Spieth.
Woods, who single-putted 11 greens in an opening round of 70, had carded one birdie and 12 pars in his first 13 holes.