Rookies set clubhouse target
Masters rookies Jonas Blixt and Kevin Stadler set the early clubhouse target at Augusta National, but several veterans look set to catch them.
Blixt was four under par with four holes to play before bogeys on the 15th and 18th meant he had to settle for a two-under 70, matching the score posted moments earlier by Stadler, who was making history with dad Craig as the first father-son combination to play in the same Masters.
Blixt's late mistakes left 50-year-old Spaniard Miguel Angel Jimenez alone in the lead on four under par, one ahead of 47-year-old Steve Stricker, defending champion Adam Scott and Brandt Snedeker.
Former champions Fred Couples, 54, and Sandy Lyle, 56, were a shot further back on two under alongside pre-tournament favourite Rory McIlroy.
Scott had made the ideal start to the defence of his title as the 78th Masters got under way in perfect conditions, the 33-year-old making the most of seeing his tee shot on the first narrowly miss a deep fairway bunker by firing a brilliant approach to within three feet of the hole.
The Australian duly holed out for a birdie to kickstart his campaign to join Jack Nicklaus, Nick Faldo and Tiger Woods as the only men to win back-to-back Masters titles.
And although he failed to birdie the par-five second after his approach found a greenside bunker, the world number two then picked up further birdies on the sixth and eighth.
Playing partner Matt Fitzpatrick got off to a nightmare start with a double-bogey six, the US Amateur champion driving into trees and then pitching over the green with his third shot.
However, the 19-year-old from Sheffield hit back with a birdie on the second and remained one over par after eight holes.
McIlroy had been in danger of dropping a shot on the first after spinning his approach back off the green, but almost holed his pitch and was left with a tap-in to save par.
The 24-year-old also made par on the second after finding the same bunker as Scott, but holed from five feet for birdie on the third and also birdied the fifth.
Earlier in the day, Jack Nicklaus had been able to claim bragging rights after joining Gary Player and Arnold Palmer in getting the tournament under way.
The trio formerly known as golf's 'Big Three' - they have 13 Masters titles between them - continued their role as honorary starters by each hitting a tee shot on the par-four first hole.
And it was six-time champion Nicklaus, 74, who produced the longest drive by around two feet from 78-year-old fitness fanatic Player, with both players splitting the fairway on a hole ranked the second hardest on the course last year.
Palmer, who will undergo back surgery after the Masters, had also found the fairway with his drive, although the 84-year-old's effort was comfortably the shortest of the three.
Four-time champion Tiger Woods, missing the event for the first time following back surgery, wrote on Twitter: "It never gets old watching the honorary starters tee off. One of the oldest and best traditions in the game."
Scott followed Jimenez into the water on the 12th - at 155 yards the shortest hole on the course but one of the most treacherous - and also ended up with a double bogey to drop him back to two under par.
That was two off the lead now held by American Bill Haas, who had reached the turn in 34 and birdied the 13th and 14th, while Gallacher moved into outright second place with a birdie on the ninth.