By Steve Keating
AUGUSTA, Georgia (Reuters) - Jordan Spieth watched from atop the Masters leaderboard as the early second round starters, including world number one Jason Day, failed to close the gap on the defending champion on Friday.
Spieth, who was set to tee off among the afternoon wave on sunny but cool day at Augusta National, had a two-shot overnight cushion and it remained intact after an early challenge from New Zealand's Danny Lee stalled.
Lee cut Spieth's advantage to one with a birdie at the second but that was quickly followed by a double-bogey at the third, where he four-putted, and another birdie at fifth in a roller coaster start to his round.
American Scott Piercy through four holes, Dane Soren Kjeldsen and Spain's Sergio Garcia, through three joined Lee at four-under as he approached the turn.
Day, the hottest player in the game after winning six times in his last 13 starts, got to five-under on Thursday before his opening round unraveled as he dropped five shots in his last four holes for a 72.
Problems followed the Australian into the second round, with a bogey at the first, but the Queenslander quickly got that stroke back with a birdie on at the second and another the fifth to sneak under par and start to creep up the leaderboard.
It was another frustrating start for twice Masters champion Bubba Watson, who opened with a bogey at the first and then went into a tailspin, dropping shots at four, five and six to fall to six-over through seven and 12 behind the pacesetting Spieth.
(Editing by Andrew Both)