Miami - Reigning Masters champion Adam Scott of Australia matched the Bay Hill course record with a 10-under par 62 on Thursday to seize command at the PGA Tour's Arnold Palmer Invitational.
World No 2 Scott, hot on the heels of top-ranked Tiger Woods just three weeks before defending his Masters crown at Augusta National, fired seven birdies, two eagles and a bogey.
That was level for the course record set by American Andy Bean in 1981 and matched by Aussie Greg Norman in 1984.
"Today was just one of those days where the hole was a bit like a bucket," Scott said.
Japan's Ryo Ishikawa and American John Merrick shared second on 65, one stroke in front of Spaniard Gonzalo Fernandez-Castano.
With uncanny long-range putting that saw him sink five from beyond 20 feet, Scott produced the best opening round in Bay Hill history, two strokes better than the prior mark that was achieved 11 times, the first of them by tournament namesake Palmer himself in 1970.
"It's maybe a little surprising," Scott said. "I don't know where it came from but the putter certainly got hot."
And Scott had not played at Bay Hill since 2009, when he missed the cut.
"I just had a few frustrating years here and left it off the schedule," Scott said. "Coming back here fresh was obviously a good thing."
Scott, 33, last opened an event with a 62 at the 2011 World Golf Championships event at Firestone Country Club, where he won by four shots.
Starting off the 10th tee, Scott opened with a 19-foot birdie putt then reached a greenside bunker at the par-5 12th in two and went up and down from four feet for another birdie.
A 26-foot birdie putt at the par-3 14th was followed by a 28-foot birdie putt at the par-4 15th and his first eagle at the par-5 16th when Scott reached the green in two and sank a 36-foot putt.
Scott suffered his lone bogey at the par-4 18th, finding the left rough off the tee and with his second shot and then running a 29-foot par putt two feet beyond the cup.
Scott responded with a nine-foot birdie putt at the third and eagled the par-5 fourth, reaching the green in two and sinking a 19-foot putt.
Back-to-back birdies on the par-5 sixth, getting up and down from a greenside bunker thanks to an eight-foot putt, and par-3 seventh, on a 13-foot putt, were followed with two pars.
Scott could have set the course record but missed a nine-foot birdie putt at the eighth.
Ishikawa, ranked 83rd, is still seeking his first US PGA title after a second career runner-up effort at last year's Shriners Hospitals Open.
Ishikawa had a tap-in birdie at the fourth and made a five-footer to birdie the sixth, then sank a 14-foot birdie putt at the eighth.
Back-to-back birdies at 12 and 13 were followed by his lone bogey at 14 but he responded at 15 and 16 with back-to-back birdies and closed with a six-foot birdie at 18.
Former Masters champion Bubba Watson withdrew from the event after the first round, citing allergy issues.
"My allergies have taken over!" Watson posted on Twitter. "It's hard to focus when you're heads all discombobulated from medicine and pollen."
Leading scores on Thursday after the first round of the Arnold Palmer Invitational (par 72, USA unless noted):
62 - Adam Scott (AUS)
65 - Ryo Ishikawa (JPN), John Merrick
66 - Gonzalo Fernandez-Castano (ESP)
67 - Brandt Snedeker, Morgan Hoffmann, Paul Casey (ENG), Jamie Donaldson (WAL), Jason Kokrak, Francesco Molinari (ITA)
68 - Ryan Moore, Charles Howell, JB Holmes, Brendan Steele, Ian Poulter (ENG), Graeme McDowell (NIR)
69 - Chad Campbell, Patrick Reed, Trevor Immelman (RSA), Matt Every, Henrik Stenson (SWE), Chesson Hadley, Harris English, Chris Kirk, Sam Saunders
WD - Bubba Watson