Jason Day put together the best round of the day on Friday, while playing in the final group at the Masters.
Day carded a 4-under 68 to take the lead after 36 holes at Augusta National. He finished two rounds at 6-under-par 138.
The Australian finished second at the Masters and U.S. Open in 2011. They are his best finishes in the majors.
"What I went through two years ago, being so close to winning the event and feeling what it feels like on the weekend, is pretty chilling with the roars going through the trees on the back nine," Day said of his experience in 2011. "I've got to come out tomorrow and stay aggressive to the targets, and hopefully I play well."
Fan favorite Fred Couples carded a 1-under 71 and he shares second place with another Australian, first-round co-leader Marc Leishman, who tripped to a 1- over 73.
Angel Cabrera, a two-time major champion, posted a 3-under 69 earlier in the day to climb to minus-4. He was joined in fourth place by Brandt Snedeker (70) and Jim Furyk (71).
Four-time Masters winner Tiger Woods had an unlucky break late in his round. His third shot caromed off the flagstick on No. 15 and back into the water. That led to a bogey, and he 3-putted for another bogey at the last for a 1- under 71. Woods is tied for seventh at 3-under 141 with six others, including Adam Scott (72), Lee Westwood (71) and Justin Rose (71).
"I thought it was pretty good shot. I was pretty (mad). I was looking at making birdie, now I have to struggle and grind to not drop two shots," Woods said of the 15th. "I felt I played really well today and should have been in the 60s. I played well, especially when the wind kicked up. My score doesn't quite indicate how well I played today."
Sergio Garcia, who shared the first-round lead with Leishman, struggled to a 4-over 76, which dropped him to minus-2. Garcia shares 14th place with former champion Bernhard Langer (71) and Rory McIlroy (70).
Further down the leaderboard, defending champion Bubba Watson managed a 1-over 73 to make the cut on the number of 4-over 148. Also finishing at plus-4 was 14-year-old Tianlang Guan.
Guan carded a 3-over 75. His round included a penalty stroke for slow play.
"Tianlang Guan was assessed a 1-shot penalty for violation of Rule 6-7 of the Rules of Golf and the Tournament's Pace of Play Policy. His group, which included Ben Crenshaw and Matteo Manassero, was deemed out of position on No. 10," stated Fred Ridley, Masters Tournament Competition Committee Chairman. "Guan began being timed on No. 12 and received his first warning on No. 13 after his second shot. In keeping with the applicable rules, he was penalized following his second shot on the 17th hole when he again exceeded the 40- second time limit by a considerable margin."
Despite the penalty, Guan made the cut on the number making him the youngest player to make a cut in a major. Of the six amateurs that competed this week, Guan is the only one to make the cut.
Prior to Day's climb up the leaderboard, the Guan situation played out as did the late collapse of Dustin Johnson.
Johnson had three birdies from the ninth to 13th to grab the lead at minus-7. He coughed up six strokes in the final five holes to fall to 1-under par.
Day stumbled to a bogey on the fourth, but got that stroke right back as he birdied the par-4 fifth. He converted another birdie effort at the seventh, then parred eight and nine to make the turn at minus-3.
The 25-year-old, who won the 2010 Byron Nelson Championship, dropped in back- to-back birdie chances at 10 and 11 to grab a share of the lead at minus-5.
Day tripped to a bogey at 12th, but came right back with a birdie on 13 to again grab a piece of the lead. After a pair of pars, Day converted a right- to-left sliding birdie putt on the par-3 16th to gain the outright lead. He parred the last two to hold the 36-hole advantage.
"I was just saying, I was really, really tired after today. It just felt like a big, big grind out there," said Day, whose group needed some five hours, 45 minutes to complete their round. "I'm just happy I am in the house now."
Couples, who shared the 36-hole lead last year, had two bogeys and two birdies through six holes. He stumbled to a double bogey on the seventh after driving into the trees and knocking his second over the green.
The 53-year-old missed the green with his third, then pitched his fourth to six feet. From there, Couples 2-putted to fall four behind the leader. He bounced back with his second birdie in two days at the par-5 eighth.
Around the turn, Couples dropped his tee shot 11 feet from the hole at the 12th and poured that in for birdie. He parred five in a row before closing with a birdie at the last.
"It's such a unique place here. When I went out and played today, I didn't really know what would be a good score. I didn't know if 75 would be a good score for me, not the rest of the field, because it's just hard," Couples said. "It's a hard course. I feel like I'll be right there, and I'll take that."
Asked what would happen if he were lucky enough to win this tournament again, Couples stated, "This is my favorite tournament to play. I would probably retire from normal golf, and just come here every year and have a blast."
Leishman stumbled to bogeys at the fourth and sixth, but recovered those shots with birdies at seven and eight. He parred the ninth to make the turn at even- par for the day.
The 29-year-old Australian also parred the first four holes around the turn. Leishman stumbled to a bogey at the 14th, then parred out to share second.
"It was a good fun day out there today. I grinded it out pretty well," said Leishman. "I had a couple bogeys early and to fight back the way I did, I was happy with that."
NOTES: This is the first time Day has had the 36-hole lead in a major. He has been in this position three times on the PGA Tour, but failed to hold all three leads ... The cut line fell at 4-over-par 148 with 61 players advancing to the weekend and Watson will play as a single on Saturday ... Among those that missed the cut were Padraig Harrington, Ian Poulter (who missed the cut for the first time in nine starts at the Masters), Nicolas Colsaerts, Graeme McDowell, reigning U.S. Open champion Webb Simpson, last year's runner-up Louis Oosthuizen and Hunter Mahan.