Dublin - Geoff Ogilvy, Justin Rose and Rickie Fowler shared the lead at the Memorial on Thursday as Phil Mickelson got a jump on Tiger Woods in his chase for the world number one ranking.
Australia's Ogilvy made eight birdie putts to briefly take sole possession of the lead on eight-under. But it was a short miss on his 17th hole - the par-three eighth - that saw him finish on seven-under 65 alongside England's Rose and 21-year-old rookie Fowler.
"I putted very well - except for one little blip," said Ogilvy, who had missed a 15-foot birdie attempt at the eighth then saw his tap-in for par spin in and out
The leading trio were two shots ahead of a group that included Masters champion Mickelson - who again has a chance to supplant Woods atop the world rankings this week.
Woods, the defending champion and a four-time winner of the Memorial, rebounded after two early bogeys with back-to-back birdies at nine and 10 en route to an even-par 72.
Woods, who began play after a rain delay of some two hours, was unimpressive. He failed to birdie any of the par-fives and along with a smattering of wayward tee shots was off-base with several wedge shots as well.
Woods finally got his first birdie at the ninth, sinking a 21-foot putt from the back of the green.
He got to even-par with another birdie at 10, but couldn't gain any more ground.
"My wedges were horrible today," Woods said. "But I was encouraged at the way I was able to hit a few shots. The shape, the feel - it was more like I hit the ball last year."
Woods completed just his 10th full round of the year, after a belated start to the season in the wake of the sex scandal that made him a tabloid sensation.
After a tie for fourth in the Masters, he has one missed cut and a fourth-round injury withdrawal on his 2010 record.
Woods says the inflammation in his neck that forced him to pull out of the final round of the Players Championship hasn't completely healed, but he was well enough to play 54 holes at home on Sunday.
His struggles have put Mickelson within striking distance of the top ranking, although "Lefty" was unable to capitalize last week at Colonial where he missed the cut.
To move up this week, Mickelson must win and Woods finish out of the top four.
Mickelson has never won the Memorial, but admitted he would love to win the event hosted by Jack Nicklaus.
"I told Jack yesterday it would really mean a lot to me to win his tournament," Mickelson said. "This golf course is wonderful."
Mickelson completed his 67 without a bogey, and after teeing off on 10 came on strong late with three birdies in a row from the fifth.
"The soft greens allow you to attack a lot of the pins," Mickelson said. "It played a lot longer because the ball wasn't rolling. It was a very fun day and a lot of good scoring today."
Rose seemed refreshed by the rain delay, nabbing birdies at six of his last 10 holes after the break to seize the clubhouse lead.
Fowler was the first two attack with three straight birdies from the fourth and an eagle on the par-five seventh followed by a birdie at eight.
Ogilvy capped his outward run with a birdie at 18, then birdied the first from a deep fairway bunker.
"It was nice to hole the putts," Ogilvy said. "If anything has been missing from my game the last month or two it's been poor putting."
Mickelson was joined on 67 by Andres Romero of Argentina, South African Rory Sabbatini, Australian Jason Day and American Michael Letzig.
"It was definitely a day to make some birdies," Ogilvy said. "You want to take advantage of a day like today because this course generally won't get any easier during the week. It does give you a few chances, and it's nice to take them, for sure."
While Woods couldn't capitalize on the conditions, he said he could make up ground on Friday, provided he plays the par-fives better.
"If I take care of the par fives, I'm right there," Woods said.
Leading first-round scores on Thursday from the $6m Memorial Tournament (USA unless noted):
65 - Rickie Fowler, Geoff Ogilvy (AUS), Justin Rose (GBR)
67 - Jason Day (AUS), Michael Letzig, Phil Mickelson, Andres Romero (ARG), Rory Sabbatini (RSA)
68 - Jim Furyk, JB Holmes, Fredrik Jacobson (SWE), Spencer Levin, Steve Marino, Sean O'Hair
69 - KJ Choi (KOR), Carl Pettersson (SWE), Michael Sim (AUS)
70 - Tim Clark (RSA), Matt Jones (AUS), Adam Scott (AUS), Yang Yong-Eun (KOR)
71 - Aaron Baddeley (AUS), Alex Cejka (GER), Brian Davis (GBR), Thongchai Jaidee (THA), Vijay Singh (FIJ), Brendon de Jonge (ZIM)
72 - Nathan Green (AUS), Ryuji Imada (JPN), Martin Laird (GBR), Liang Wenchong (CHN), Rory McIlroy (NIR), Tiger Woods
73 - Stuart Appleby (AUS), Angel Cabrera (ARG), Mathew Goggin (AUS), John Senden (AUS), Henrik Stenson (SWE)
74 - Robert Allenby (AUS), Greg Chalmers (AUS), Ernie Els (RSA), James Nitties (AUS), Jeev Milkha Singh (IND)
75 - Graham Delaet (CAN), Noh Seung-Yul (KOR)
76 - Marc Leishman (AUS), Rod Pampling (AUS)
77 - a-An Byeong-Hun, Camilo Villegas (COL), Mike Weir (CAN)