Shane Lowry will take a two-shot lead into the final day of the US Open at Oakmont Country Club but he will still have four holes of his third round to complete on Sunday morning.
Thursday's heavy rain and storm delays meant tournament organisers had been playing catch up all week but with good weather forecast for Sunday, the final round should be completed on time.
That rain earlier in the week has softened up the notoriously tough Pennsylvania layout and - after many predicted an over-par winning score - Lowry will head into day four at five under.
The Irishman fired a 70 in his second round on Saturday morning but showed no signs of fatigue when he returned to start round three, carding five birdies and two bogeys to establish a cushion ahead of American Andrew Landry, who had five holes remaining.
Landry's countryman and playing partner Dustin Johnson was a further shot back alongside Spain's Sergio Garcia - who is playing with Lowry - and England's Lee Westwood who was playing the 16th when play was suspended due to darkness at 8.49pm.
South African Branden Grace fired a 66 to set the clubhouse target at one under, one shot clear of American Scott Piercy and two ahead of the group including World Number One Jason Day.
All of the top seven players will go in search of a first Major Championship on Sunday, with Garcia, Grace, Johnson and Westwood all having experienced near-misses.
Johnson entered round three with a one-shot lead over Landry and at one point there was a four-way tie on a dramatic evening of ebb-and-flow, but it was Lowry who ended the day on top.
"We all know that this course can jump up and bite you in a split second," he said.
"I'm two ahead with 22 holes left, let's not get ahead of ourselves.
"These are the best golfers in the world behind me, Dustin and Jason. Sergio played lovely today. I have to go out and do what I've been doing all week. I'm really looking forward to tomorrow.
This is exactly where you want to be. I've been beating myself up over the last six months trying to get in this position. I'm here now. I might as well enjoy it while I'm here - Shane Lowry
Lowry bogeyed the second but three birdies in four holes from the fourth - capped by an excellent 22-footer on the seventh - moved the WGC - Bridgestone Invitational champion into the lead at four under.
He then bogeyed the eighth as Landry moved ahead with an excellent curling 20-footer but another Lowry birdie on the ninth levelled things up before a dropped shot by Landry on the same hole.
Lowry then put his approach on the 12th to two feet to give himself some breathing space.
Johnson birdied the first and despite bouncing straight back from a double-bogey on the third, further dropped shots on the sixth and tenth saw him fall back.
Westwood was one under for his round after a rollercoaster of an evening which saw a chip-in birdie on the second and a hole-out from 130 yards on the fifth for an eagle, along with two further birdies and four bogeys.
Garcia had two birdies and two bogeys in his round while Piercy was two over for his round after 13 holes.
Grace had six birdies and two bogeys including a 15-foot gain on the last that got him into red numbers.
