Georgia - Former Masters champion Trevor Immelman was delighted after shooting a four-under 68 to headline a strong South African performance on the opening day at Augusta National Golf Club.
Immelman, who last year finished 60th after starting with a round of 78, hoped to maintain his momentum after an impressive first round on Thursday.
"I am obviously very happy with my round. I played some solid golf," Immelman said.
"I did not hit too many good shots early, but just hung in there and on the back nine I hit some quality shots and made some good putts.
"Any time you can hit under par in a Major, you are doing well, so I am really happy with it, but there is still a lot of golf to be played, so we have to look at the situation on Sunday."
Immelman, who won the tournament in 2008, was tied for fourth after the first round, lying two shots behind leaders Marc Leishman and Sergio Garcia and one stroke behind Dustin Johnson.
Fellow South African Tim Clark was on two under, while Ernie Els and Charl Schwartzel carded a one-under 71.
European Tour to Dubai leader Richard Sterne was on one over par, Louis Oosthuizen, who last year lost in a playoff to Bubba Watson, was two over, while George Coetzee was a further stroke behind.
Two double-bogeys on the back nine saw rookie Branden Grace finishing on six over.
Els, who missed out on playing at the Masters last year, started with a bogey, but birdied three of the par-five holes and eagled the 15th.
"On the 15th I hit a good drive and a six iron and then had a good putt from 10 feet. That really highlighted my round," Els said.
"I bogeyed some soft holes and I will try to sort that out in the next round, but I am glad that I scored under par in my comeback round after missing last year."
Schwartzel also struggled at the opening hole and landed deep in the trees to the right of the fairway with his tee-shot. His left-handed iron caught a branch and stayed in the trees, resulting in a double-bogey six.
The 2011 champion then played a one-over five at the third to lie on three over after only three holes.
"That was a hard start and that was not quite what you were looking for after quite a few months of preparations," Schwartzel admitted.
On a tough course like the Augusta National, he believed it was easy to let a round slip quickly.
"I have always said patience around this course is what you have to implement.
"That is what I had to do. I had to try and stay patient and believe that if I kept hitting good shots, I would start eating back at it. Fortunately, that was the case.
"I thought I grinded well and can take a lot from that round."
Oosthuizen played solid golf in the opening holes, but then had back-to-back bogeys on the sixth and seventh. Although he managed to birdie three of the four par-fives, he dropped a further three shots at the ninth, 12th and 17th, to finish eight strokes off the pace.
Sterne, who finished 25th in 2008, was consistent through his round, which included two birdies and three bogeys. He would have finished on par 72, had he not missed a putt on the 18th to finish the hole with a bogey.
Coetzee, in contrast, managed to sink a 10-footer at the 18th to finish three-over for the round, alongside defending champion Watson.
Odds on favourite Tiger Woods carded a two-under 70 to lie within striking distance ahead of the second round.
Collated scores on Thursday after the first round of the 77th Masters at par-72 Augusta National Golf Club:
66 - Marc Leishman (AUS), Sergio Garcia (ESP)
67 - Dustin Johnson (USA)
- David Lynn (ENG), Rickie Fowler (USA), Gonzalo Fernandez-Castano
(ESP), Trevor Immelman (RSA), Fred Couples (USA), Matt Kuchar (USA)
69 - Jim Furyk (USA), Zach Johnson (USA), Adam Scott (AUS)
- Kevin Na (USA), David Toms (USA), Tim Clark (RSA), Lee Westwood
(ENG), Brandt Snedeker (USA), Justin Rose (ENG), KJ Choi (KOR), John Huh
(USA), Tiger Woods (USA), Jason Day (AUS)
71 - John Peterson
(USA), Ryan Moore (USA), Ryo Ishikawa (JPN), Charl Schwartzel (RSA),
Luke Donald (ENG), Ernie Els (RSA), Bernhard Langer (GER), Bo Van Pelt
(USA), Angel Cabrera (ARG), Phil Mickelson (USA)
72 - Russell
Henley (USA), Brian Gay (USA), Mike Weir (CAN), Peter Hanson (SWE), John
Senden (AUS), DA Points (USA), Vijay Singh (FIJ), Yang Yong-Eun (KOR),
Martin Kaymer (GER), Fredrik Jacobson (SWE), Rory McIlroy (NIR), Bill
Haas (USA), Jason Dufner (USA)
73 - Sandy Lyle (SCO), Larry Mize
(USA), Richard Sterne (RSA), Webb Simpson (USA), Graeme McDowell (NIR),
Michael Thompson (USA), Thomas Bjorn (DEN), Steve Stricker (USA), Guan
Tianlang (CHN), Keegan Bradley (USA)
74 - Jose Maria Olazabal
(ESP), Nicolas Colsaerts (BEL), John Merrick (USA), Mark O'Meara (USA),
Jamie Donaldson (WAL), Lucas Glover (USA), Francesco Molinari (ITA),
Louis Oosthuizen (RSA)
75 - Stewart Cink (USA), Bubba Watson
(USA), Scott Piercy (USA), George Coetzee (RSA), Matteo Manassero (ITA),
Henrik Stenson (SWE)
76 - Ted Potter (USA), Kevin Streelman
(USA), Robert Garrigus (USA), Carl Pettersson (SWE), Ian Poulter (ENG),
Steven Fox (USA), Ben Curtis (USA), Martin Laird (SCO), Paul Lawrie
(SCO), Hunter Mahan (USA)
77 - Nathan Smith (USA), TJ Vogel (USA)
78 - Padraig Harrington (IRL), Thorbjorn Olesen (DEN), Michael Weaver (USA), Nick Watney (USA), Branden Grace (RSA)
79 - Tom Watson (USA), Thaworn Wiratchant (THA), Craig Stadler (USA), Hiroyuki Fujita (JPN)
80 - Ian Woosnam (WAL), Ben Crenshaw (USA)
83 - Alan Dunbar (NIR)