Rory McIlroy set the clubhouse target on a windswept second day of the Masters, as defending champion Jordan Spieth battled to maintain his lead and his composure.
Seeking a first green jacket in order to complete the career grand slam, McIlroy's chances looked slim when he followed two early birdies with a double bogey on the fourth and bogeys on the fifth and 11th.
At that stage he was eight shots behind Spieth after the world number two birdied the first and third in pursuit of becoming just the fourth player after Jack Nicklaus, N ick Faldo and Tiger Woods to successfully defend the year's first major championship.
However, Spieth who set records for the highest number of birdies (28) and lowest 36 and 54-hole totals in Masters history last year, then four-putted the fifth from 50 feet run up a double bogey, bringing back unhappy memories of doing the same on the eighth hole in the final round of the Open at St Andrews last year.
A birdie on the eighth looked to have steadied the ship, but Spieth then bogeyed the ninth and 10th and was visibly - and audibly - annoyed at being timed for slow play as he wanted to wait for the wind to die down on his approach to the 11th.
McIlroy took full advantage with birdies on the 13th, 15th and 16th and the fist pump when he saved par from the trees on the 18th told its own story.
US Amateur champion Bryson DeChambeau, who was playing alongside Spieth, had birdied the 11th and 12th to join McIlroy on three under, whose 71 equalled the lowest score of the day and left him one ahead of Danny Lee and Scott Piercy, who were also safely in the clubhouse.
"I t was very difficult," McIlroy told ESPN. "It's very hard to select a club. On the 12th tee I felt a little lull in the wind and hit it straight away. Once you get it where you feel it you have to hit it and trust it which is the hardest thing out there. I think anything under par today is a very good score.
"I definitely feel like I am coming in with not as much hype or anticipation as last year. You have Jordan as defending champion, Jason (Day) getting to number one off a couple of wins, Adam (Scott) having a couple of wins - I felt I was just part of the narrative instead of just being the narrative and I like that position.
"I feel great. I feel so much better than I did yesterday. I played the last three holes on two over and today I played last six holes in three under today so I am really happy with how I battled and ground it out and I'll have to do the same tomorrow."