Shane Lowry opened up a commanding four-shot lead as the third round of the US Open was completed at Oakmont Country Club on Sunday morning.
The Irishman took to the course at 7.00am with a two-shot cushion and four holes to play after darkness brought an end to proceedings on Saturday but he had lost none of the previous evening's momentum.
He made birdies on the 15th and 17th before holing an excellent clutch putt for par on the last to sign for a 65 and a seven under par total.
American duo Dustin Johnson and Andrew Landry were his nearest competition with England's Lee Westwood and another American, Daniel Summerhays, a further shot back.
South African Branden Grace was at one under after setting the clubhouse target with a 66 on Saturday, a shot clear of Sergio Garcia and Scott Piercy.
Lowry knows how to win against an elite international field having claimed the WGC - Bridgestone Invitational last year but, like all the players at par or better, he will be going in search of a first Major Championship on Sunday afternoon.
The 29 year old got straight into his stride as he put his approach on the 15th to 11 feet for a birdie and with Landry dropping a shot on the 14th, the lead was up to four shots.
A birdie from Johnson on the 15th cut the gap but Lowry was in supreme form, firing another pinpoint iron to seven feet to move the lead back to four.
His second to the last was not as impressive and he left himself ten feet for par but a confident putt resulted in a fist-pumping celebration and a position of dominance heading into round four.
"It's probably the best round of my career," he said. "To come back out this morning and get two birdies is huge. If you would have given me four pars, I would have stayed in bed.
"I've just got to go out and play my own game. No matter what happens, I just have to get up and play the next shot. I'm sure there are going to be little twists in the tale this afternoon, I will be expecting that, and we will just have to see how it goes.
I'm looking forward to the final round and looking forward to what could happen. I let myself think about what could happen today, you know this could be a very special day - Shane Lowry
"But when it comes back down to it, I'll just get back down to business."
Landry had made a second consecutive bogey on the 15th and, for the second time this week, his chances looked to be fading. But a birdie on the 17th followed by a sensational 45-foot putt on the last launched him back up the leaderboard.
Westwood began his day with a par putt on the 16th and he got back to the clubhouse with the minimum of fuss while Summerhays - an alternate this week after losing out in a play-off in qualifying - drove the par four 17th to make an eagle and move into the mix.
Spaniard Garcia dropped shots on the 15th and 16th after finding sand as his challenge faltered while Piercy parred is way home.
World Number One Jason Day was then at one over alongside Americans Zach Johnson and Bryson DeChambeau.
