Shane Lowry is five shots off the pace after the opening round at the Phoenix Open, where Matt Kuchar shot a seven-under-par 64 to hold a one-shot lead over the in-form Hideki Matsuyama and Brendan Steele.
Lowry hit a 69 and after bogeying the first, hit three birdies in the next four holes to move into contention at the TPC Scottsdale's Stadium Course.
The Offaly man then began the back nine with another birdie at 10 but finished with a disappointing bogey to share 28th place.
Padraig Harrington is one over following a 72. He bogeyed the sixth and 12th, but birdied 13 for one over.
American Ryder Cup star Kuchar made five birdies and holed a 20-foot eagle effort on the 13th where a typically large crowd were out in force.
Having birdied the first two holes, Kuchar had to wait until the 11th for his next gain, where he converted from 15 feet.
He almost followed his eagle on the 13th with another on 15 - his chip leaving a tap-in birdie, although he was jeered by the 20,000 crowd around the famous par-three 16th when his tee shot found the bunker, before receiving a warmer reception by getting up-and-down for par.
The 38-year-old tapped in for another birdie on the 17th and it could have been even better for Kuchar had he not misread his nine-footer at the last.
Japan's Matsuyama has won on four of his last eight starts to climb to fifth in the world rankings and again impressed with six birdies in a flawless round.
Last year's winner told pgatour.com: "I wish I knew why I play well here, but I did hit the ball very well today ... a lot of good shots.
"I have had such good success here and played well here."
He was joined on six under by American Steele, who holed out from 193 yards for eagle on the 14th as he came home in 30.
Korea's Byeong Hun An was joined by Americans John Peterson, Robert Garrigus, Scott Brown and Chris Kirk on five under, with Scotland's Martin Laird leading the British challenge on four under.
Justin Thomas gained the loudest roar of the day at 16 when he almost holed his tee shot, tapping in for birdie en route to a two-under 69.