A Masters second round that tested how top golfers handle adversity saw Tiger Woods stumble, Jason Day take the lead and teen Guan Tianlang make the cut despite a rare slow-play penalty.
Day, hoping to be Australia's first Masters champion, shot a four-under par 68 to stand on six-under 138 and take a one-stroke lead over countryman Marc Leishman and Fred Couples, trying at 53 to become the oldest major winner.
"It's a hard course out there," Couples said. "They put most of the pins in, I thought, really hard spots."
Breaking Australia's Masters jinx, a hex best known by the frustrations of Greg Norman's near-misses, weighs on Day's mind as he looks down on the rest of his rivals as the weekend looms.
"Obviously there's a lot of pressure on my shoulders, being from Australia and no Australian has ever won the event," he said. "They have been very, very close, but I've just got to try to get that out of my mind and just plug away."
Top-ranked Woods took a share of the lead late before a demoralising setback at the par-5 15th when his ball hit the flagstick and went into a water hazard. He shot a 71 to stand on 141, among 26 sub-par players within five of the lead.
"I thought I played really well, a round that should have been in the 60s," Woods said. "I played really well."
Woods, a 14-time major champion chasing the all-time record of 18 majors won by Jack Nicklaus, seeks his first major title since the 2008 US Open and first Masters victory since capturing his fourth green jacket in 2005.
Guan Tianlang, the 14-year-old Chinese schoolboy who became the youngest player in Masters history, became the first player in a major to be assessed a slow-play penalty since France's Gregory Bourdy at the 2010 PGA Championship.
"I respect the decision they make," Guan said. "This still is a wonderful experience for me. I have enjoyed playing in the Masters and I think I did a pretty good job."
After being warned and having his pace timed, Guan was given the penalty stroke for a bogey at 17, putting him on the eventual cut line and forcing him to wait until the last group finished to know if he would play on the weekend.
Guan finished on 75 in the second round and on four-over 148 for 36 holes, right on the limit that included 61 players within 10 strokes of the lead.
"Today is pretty hard because if you're timed only 40 seconds, it's pretty hard because you need to make the decision," Guan said. "The wind switched a lot."
A day after 45 players fired par or better, wind and tougher pin positions over the 7,435-yard layout kept the world's top golfers struggling simply to hold their positions.
"It was tough. There were a few pins tucked away," Leishman said. "A few of the easy holes were made tough because of the wind. I was pleased at the way I was able to fight back."
Couples, the 1992 Masters champion, has teased age history at the Masters before in recent years, leading after the first round in 2010 only to finish sixth and leading after the second round last year only to share 12th.
The oldest champion in major golf history was Julius Boros, who was 48 when he won the 1968 PGA Championship. The oldest winner in Masters history was Jack Nicklaus, who won his 18th and final major crown at age 46 at the 1986 Masters.
Argentina's Angel Cabrera, the 2009 Masters winner, birdied five of the last six holes to fire a 69 and stand two off the pace at 140 alongside Americans Jim Furyk and Brandt Snedeker.
At 15, Woods struck the flagstick with his third shot and saw it roll into the water.
"I thought it was a good one," Woods said. "I was pretty pissed.
After a penalty stroke, he repeated the shot and then made a tap-in bogey.
"From making birdie there, I've got to struggle just to lose two shots," he said. Woods was in a group at 141 that included Australian Adam Scott, American Jason Dufner, South Korean K.J. Choi and Englishmen Lee Westwood, Justin Rose and David Lynn. Only Woods among them has ever won a major.
A pack on 142 included 2011 Masters winner Charl Schwartzel of South Africa, 1985 and 1993 Masters champion Bernhard Langer of Germany, Spaniards Sergio Garcia and Gonzalo Fernandez-Castano, Australian John Senden and Northern Ireland's Rory McIlroy, whose round of 70 included an eagle at eight.
"Digging in and grinding it out was pleasing for me," McIlroy said. "The eagle on the eighth really got me going. A 70 was a good score today. You had to be really disciplined.
"The wind was in a real unusual direction. It's a tough enough course as it is without wind like that."
Dustin Johnson was a victim of tougher conditions, playing the last five holes in six-over after having led by two strokes.
Among those who missed the cut were South Korean Yang Yong-Eun, American Webb Simpson, Northern Ireland's Graeme McDowell, South African Louis Oosthuizen and Ireland's Padraig Harrington -- all past major winners.