Luke Donald made a flying start in his opening round at the US Open, finishing Thursday as the outright leader in a rain-interrupted day at Merion.
The world number six rose to the top of the leaderboard after he birdied three consecutive holes to move four-under-par, before bad light ended play with Donald through 13 holes.
Only half the field were able to completed their rounds, following a torrential thunderstorm in Pennsylvania that prompted a three-and-a-half hour delay, less than two hours after the first group teed off.
Another brief stoppage later in the afternoon held up play for around 45 minutes, after a smaller downpour capped a frustrating stop-start introduction to the second major of the 2013 season.
Donald sits one shot clear of Phil Mickelson and Adam Scott, the American defying exhaustion after flying in to Philadelphia at 4am, to card a score of three-under-par 67, which was his best opening round at the US Open since 1999.
Meanwhile, Masters champion Scott carded four birdies and a single bogey, through 10 holes he completed alongside Rory McIlory and Tiger Woods, to walk off the course on Thursday in a tie for second.
But, while the Australian was disappointed to call time on his opening round early, Woods will have been grateful to get back to the clubhouse after appearing to struggle with an injury to his left wrist.
The world number one made an inconsistent start with four bogeys and two birdies leaving him on two-over-par, while McIlroy finished with a bogey on the 11th to take him back to level-par.
Defending champion Webb Simpson is currently tied-fourth on two-under-par after he birdied the third and fourth on his way to completing eight holes, with Australian duo Alistair Presnall and Matthew Goggin on the same score through six.
Ian Poulter and Charl Schwartzel were the first players to get to three-under-par on Thursday, but neither could maintain their early momentum, finishing the day on 71 and 70.
Lee Westwood was another to undo some fine early work, after double-bogeying the 12th following an unfortunate collision with the wicker-basket on top of the pin, before finishing with a par on the 13th to finish the day on one-under par.
US Open Leaderboard: 1st -4 Luke Donald (12); T2 -3 Phil Mickelson (F), Adam Scott (11); T4 -2 Webb Simpson (8), Matthew Goggin (6), Alistair Presnell (6); T7 -1 Nicolas Colsaerts (F), Lee Westwood (13)...
T16 LEV Charl Schwartzel (F), Rory McIlroy (11); T35 +1 Justin Rose (F); T51 +2 Tiger Woods (10).