GRAEME McDowell and Shane Lowry carded solid if unspectacular opening rounds as play got underway in the 95th US PGA Championship.
McDowell went around in level par, with Lowry a shot further back - six behind early leader Jim Furyk.
However, there was further bad news for Padraig Harrington whose recent poor form continues. He is currently six over par after 16 holes, and already struggling to make the cut.
Defending champion Rory McIlroy, who has been watching videos of his eight-shot win last year for inspiration, made a brilliant start to his first round, making birdies from short range on the first, third and fourth holes.
But the former world number one then saw his approach to the fifth spin back into the water at the front of the green and did well to hole from eight feet to drop just one shot.
Lee Westwood, who led by two shots going into the final round of the Open before finishing third, was also two under after birdies at the first and fifth, while Spain's Miguel Angel Jimenez was faring even better.
The 49-year-old bogeyed the first but birdied the next five holes to lie four under alongside 51-year-old Kohki Idoki of Japan, the 2013 Senior PGA Champion.
Fresh from winning his eighth WGC Bridgestone Invitational on Sunday by seven shots, Woods started on the back nine and holed from eight feet for par on the 10th after charging a long-range birdie attempt past the hole.
The world number one, who has gone a record 17 majors without a win since the 2008 US Open, then missed the green on the par-three 11th but chipped to within three feet of the flag to save par.
A creek which runs across the 13th fairway around 300 yards from the tee meant Woods hit an iron off the tee, despite the par five measuring 598 yards, but after another iron left him 150 yards from the green the 37-year-old fired a superb approach to within two feet of the flag to set up his first birdie of the day.
Woods also birdied the par-three 15th, holing from 10ft, and saved par from a greenside bunker on the 18th to be out in 33.
Garrigus was in the second group out at 7:25am and birdied the 11th, 12th and 13th before a bogey on the 18th, but hit back with further birdies on the second and fourth.
He was joined on four under by Canada's David Hearn, who had bogeyed the first hole but hit back with birdies at the second, fourth and sixth to be out in 33 before picking up further shots on the 10th and 11th.
Woods had an excellent chance for another birdie on the second after an excellent approach, but his putt from three feet never even touched the hole.
Casey made no such mistake on the seventh, the former Ryder Cup star's fifth birdie in seven holes taking him to three under and just one behind Hearn and former US Open champion Jim Furyk.