FIRST ROUND LEADERBOARD:
(US unless stated)
-6 M Weir (Can) -4 P Hanson (Swe) -3 D Duval, T Hamilton, R Barnes -2 R Mediate -1 G McDowell (Ire), D Weaver - am, L Glover, D Toms, P Mickelson, A Scott, O'Hair
Selected others:Level S Garcia (Spa) +4 T Woods +5 P Casey (Eng) +6 P Harrington (Ire)
Weir's 64 was one shot off the US Open record
Canadian Mike Weir fired a stunning 64 to lead after the rain-delayed first round of the US Open at Bethpage.
The 2003 Masters champion made the most of sunny afternoon conditions to set the pace at six under after Thursday's virtual washout.
Sweden's Peter Hanson was two shots back with former Open champions David Duval and Todd Hamilton and fellow American Ricky Barnes on three under.
Phil Mickelson was one under with Tiger Woods back on four-over after a 74.
The first round resumed at 0730 local time (1230 BST) on Friday after only three hours' play was possible because of torrential rain and a waterlogged Bethpage Black Course on Thursday.
Northern Ireland's Graeme McDowell and American amateur Drew Weaver each posted one-under 69s to set the early pace during the overcast morning session.
"I've led a few majors after day one," McDowell said.
"It's not really what I'm trying to do. I'm just trying to stick around for the weekend. I'm trying to position myself as well as I possibly can and compete in Sunday afternoon."
It's not like I was hitting it all over the place
When the skies lightened, Weir roared through the field with eight birdies, marred only by a double bogey at the par-four 6th.
"It was a big advantage to miss the weather yesterday," said Weir. "All of us on this side of the draw got a good break.
"It was one of those days I wanted to take advantage. I wanted to keep the pedal down."
Weir finished one off the record for the lowest round in US Open history, carded by Vijay Singh (2nd round, Olympia Fields, 2003), Jack Nicklaus and Tom Weiskopf (both 1st round, Baltusrol lower, 1980) and Johnny Miller (4th round, Oakmont, 1973).
The popular Mickelson was cheered all the way round by the New York galleries who voiced their support of his wife Amy who has breast cancer.
The world number two, who began at the 10th, reached three under after 13 holes but dropped shots at the 6th and 7th.
Woods, the defending champion, picked up where he left off at one over but immediately dropped a shot on the 7th green.
Birdies at 11 and 14 made amends but Woods leaked a further four shots in his last four holes.
"I was even par with four to go," Woods said. "I mean, it's not like I was hitting it all over the place. I was hitting a lot of good shots. Unfortunately, I just didn't finish off the round the way I needed to."
Ireland's three-time major champion Padraig Harrington, who has missed the cut in three of his last four events on the PGA Tour, ended on six under playing alongside Woods and Masters champion Angel Cabrera, who finished four over.
The English trio of Ian Poulter, Ross Fisher and Oliver Wilson carded level-par 70s alongside Spain's Sergio Garcia.
"Good, solid start," Poulter said, "I'm very happy, three birdies, three bogeys, and it's a nice start to a US Open."
Lee Westwood shot a 72, as did Northern Ireland's Rory McIlroy, while Martin Laird, Scotland's lone competitor, and Darren Clarke, also of Northern Ireland, shot four-over 74s.
But England's world number three Paul Casey will need to get back on track on Saturday after a 75.
The players who resumed their unfinished first rounds on Friday will not begin their second rounds until Saturday, while the other 78 in the draw were set to embark on their second rounds on Friday.
The forecast for the weekend, though, is for heavy rain on Saturday and light rain on Sunday.
Tournament organisers the United States Golf Association insist the US Open will be decided over not fewer than 72 holes, meaning a Monday finish is on the cards.