Jordan Spieth strengthened his position at the top of the Masters leaderboard on Friday as his main rivals all suffered mishaps at Augusta.
By the time reigning champion Spieth, who led throughout last year's tournament, began his second round at 12:55pm local time (5:55pm BST), his overnight lead of two strokes was still intact, the earlier starters having struggled to make headway.
And Spieth soon doubled that advantage by birdieing the first and third to get to eight under, his second gain courtesy of a delightful approach to two feet.
Danny Lee was Spieth's nearest rival at four under, with Justin Rose, Paul Casey, Scott Piercy and Shane Lowry a further shot back.
However, Rory McIlroy and Jason Day were both enduring frustrating rounds on a day when lightning-fast greens and some fiendish pin positions resulted in scoring proving tricky, for all bar Spieth at least.
World number three McIlroy briefly reached four under with gains at the second and third, before going double-bogey, bogey over the next two holes. He remained one under for the tournament, seven adrift of Spieth, through 10 holes.
Day, meanwhile, was suffering further misery on the back nine, which he took 41 strokes to complete on Thursday.
Having turned in 34 to get to two under, Day gave a shot back on 11 despite a perfect drive and then made a mess of the par-five 13th, which represents one of Augusta's easiest birdie opportunities.
The Australian found a tributary of Rae's Creek in front of the green with his second shot and subsequently ran up a six to drop back to even par.