AUGUSTA, Georgia (Reuters) - Australian Marc Leishman regained the Masters lead in the second round on Friday while the tournament's feel-good story took an unfortunate turn when 14-year-old Guan Tianlang was penalised for slow play.
Leishman, the overnight leader after an opening 66, remained at six under par after birdies at the seventh and eighth holes made up for two earlier bogeys for a one-shot lead over veterans Fred Couples and Jim Furyk and a charging Tiger Woods.
Woods, a four-times winner looking for his first major in five years, roared up the leader board three birdies in four holes from the fifth.
Standing four under par was 2009 champion Angel Cabrera of Argentina, who birdied five of the last six holes after a bumpy start for 69 and a four-under 140 total.
While that quartet fought at the top of the leader board, China's Guan was dealt a blow to his chances of making the cut when he was penalized a stroke for slow play after he had apparently posted a par on the 17th hole.
Guan, the youngest competitor ever in the Masters, had to sign for a bogey-five at 17 and his three-over 75 gave him a 36-hole total of four-over 148, which was in jeopardy of missing the cut, depending on the scores of Friday's late starters.
Earlier, sunshine and roars replaced damp and dreary morning conditions at Augusta National with eagles and birdies flying, though swirling winds tested the golfers.
Big-hitting American Dustin Johnson temporarily seized the lead with birdies at the fourth, ninth, 10th and 13th holes took him to seven under par for the tournament.
A bogey at 14 was followed by double-bogey at the par-five 15th, bogey at 17 and another double-bogey at the last that sent him crashing to one-under-par 143.
Couples, the 53-year-old 1992 champion, finished a see-saw round with a birdie at 18 to move within one stroke of the lead. Couples carded five birdies, two bogeys and a double-bogey for his 71.
Furyk, the 2003 U.S. Open winner, had three birdies against a lone bogey through 13 holes to join Couples on five-under.
Players were mainly moving in the wrong direction during the morning's dreary conditions, but after the sun broke through the roars returned as galleries celebrated a convocation of eagles.
World number two Rory McIlroy used an eagle at the par-five eighth hole to overcome bogeys at two of his first three holes on his way to a two-under-par 70 for two-under 142.
Charl Schwartzel of South Africa, the 2011 champion, was one of those to take advantage of the par-five second hole, draining a short eagle putt and following that with a birdie at the third, before two bogeys left him at two-under at the turn.
Bill Haas holed out from the fairway at the ninth for eagle and was nearly joined in the cup by playing partner Jason Dufner on the next shot. Dufner's ball rolled by the edge of the hole and he settled for a four-foot birdie.
Haas shot 72 for one-under 143, and Dufner posted a 69 for three-under-par 141.
Spain's Sergio Garcia, who had shared the first-round lead after a 66, went in reverse during the gloomy morning hours and soared to a 76 to stand two under par for the championship.
His compatriot Gonzalo Fernandez-Castano, who opened with a 68, also struggled to a 74 to join Garcia with a 142 total.
The precocious Guan, who shot an impressive 73 on Thursday, received his first warning at the 13th hole after his second shot, and was penalized following his second shot at the 17th.
Guan said he took extra time trying to gauge the tricky wind conditions and respected the decision.
"This still is a wonderful experience," Guan, who was still in the running to make the cut, said in a televised interview. "I enjoyed this week so far and think I did a pretty good job."
(Editing by Frank Pingue)