Dustin Johnson opened up a one-shot lead as the US Open was set for a dramatic conclusion at Oakmont Country Club.
Shane Lowry came into the final round with a four-shot lead but while he turned in 38 to fall to four under, Johnson picked up two shots on his front nine to edge his nose in front.
Both men are going in search of their first Major Championship in Pennsylvania, as is Spaniard Sergio Garcia, who also turned in 33 to sit three shots off the lead alongside American Scott Piercy.
Jim Furyk fired a closing 66 to set the clubhouse target at one under, where he was joined by South African Branden Grace who had eight holes to play.
Big-hitting American Johnson looked like he meant business as he hammered a perfect 378-yard drive down the first but he could not take advantage while Lowry made a nervy par putt to stay at seven under on the same hole.
Piercy made a birdie-birdie start to join the group at two under alongside Grace who had a gain on the second, while Johnson set up a birdie as the 31 year old drove the green on the same hole and cut the lead to three shots.
That achievement with a devilishly difficult pin position was made to look even more impressive as Irishman Lowry fell victim to the fast, sloping green to drop a shot, with Grace also surrendering a stroke on the third.
Garcia made a gain on the fourth to get back into red numbers and he followed it with another to join the group at two under.
He was not making as big a move as American Furyk, however, with the 2003 champion recording birdies on the first, fifth, seventh and 11th to sit at one under.
Lowry saw a birdie putt on the fourth lip out at 90 degrees and then got into bunker trouble on the fifth, making a brilliant two-putt to drop just a single shot which brought a fist-pumping celebration.
Garcia three-putted the seventh to drop a shot but bounced straight back with a sensational holed bunker shot on the eighth before getting up and down well for a par save to turn in 33.
Furyk made a gain on the 17th to get the crowd excited but he bogeyed the last to sign for a 66 and set the clubhouse target.
The local crowd produced an even greater cheer on the ninth when Johnson put his approach to eight feet and joined the lead before Lowry got in bunker trouble on the same hole and slipped a shot back.
England's Lee Westwood had started the final round five shots off the lead but dropped eight shots on his front nine to fall out of contention.
