US Open Golf 2016 Leaderboard: Live Updates and Storylines to Watch for Sunday

The greatest moment of Shane Lowry's professional golf career may be just a few hours away from reality.

The bearded Irishman put his signature all over the U.S. Open when he fired a 65 in the third round, and he goes into Sunday's championship round with a four-stroke lead over Dustin Johnson and Andrew Landry.

Lowry had played 14 holes of the third round when darkness called a halt to the activity Saturday night. Sleeping on the lead obviously agreed with Lowry, as he came out Sunday morning and played the final four holes at two under par to push his lead to four strokes.

He drained a 12-foot putt on the 15th hole for his first birdie Sunday morning and then nailed a seven-foot birdie putt on No. 17 after executing a strong wedge out of dense rough.

Lowry has climbed the leaderboard in steady fashion, which included playing the weather-delayed second round early Saturday morning. He shot an even-par score of 70 in that round.

He was able to take the lead by himself in Round 3 with birdies on the sixth and seventh holes.

“I knew the putt I had on No. 7 was to take the lead on my own, which is, you know, it’s nice. I’m quite aware of what’s going on around me,” Lowry told Michael Whitmer of the Boston Globe. “My game is good. Feel very comfortable out there.”

Lowry and Landry will tee off at 3:30 p.m. ET in the final pairing of the day. Johnson and England's Lee Westwood, who is five strokes behind at two under, will tee off 10 minutes earlier and chase Lowry throughout the final round.

Johnson, the second-round leader, struggled through much of the round and shot a one-over 71 on moving day. 

Johnson's problems started on the second hole when he hooked a drive into a refreshment stand that was far off line. He hit a tremendous recovery and got his par, but he double-bogeyed the third hole and lost sole possession of the lead.

The rest of the round was about near-misses for Johnson. He had just three birdies during the round, as he was unable to connect on a number of good opportunities with his putter.

"Felt like I hit a lot of good putts that didn't go in the hole, just burning the edges," Johnson told Ian O'Connor of ESPN.com. "A few lip-outs. But I mean, it's the golf course. It's tough to make putts on it. I'm still feeling good about where I'm at. A lot of golf to go. Golf swing feels good. So I'm happy with where I'm at."

Johnson has endured several near-misses at major championships in the past, with the most notable occurring at Chambers Bay in last year's U.S. Open. A brutal three-putt from 12 feet on the 72nd hole cost him both the title and a chance to compete in a playoff. 

Westwood and Daniel Summerhays are right behind Johnson and Landry, while South Africa's Branden Grace is one under par. No other players in the field are under par heading into the last round.

While Jason Day is eight strokes behind Lowry at one over, he should not be counted out. Day has responded quite well after his opening round of 76, coming back with a 69 in the second and a 66 in the third.

Day, the No. 1 player in the world, would almost certainly need a bit of a collapse from Lowry to have a good chance to win this tournament, but his game is moving in the right direction. No player has won a major championship with an opening round of 76 or worse since Jack Fleck won the 1955 U.S. Open.

Day told Elizabeth Bloom of the Pittsburgh Post-Gazette that his game and concentration have improved with each round: "I had a lot of clubs that were in between the first round. The second round felt a lot better. Obviously, today, I kind of started firing not on all cylinders, but started firing at my target and felt really good about my swing.”

While Day has a long way to go to get into serious contention for the title, he knows that the window for a championship at Oakmont is at least partially open.

"I just wanted to play hard and fast for it, and I think the harder the better, like a normal U.S. Open Sunday should be," he said. "I think it would be fun for everyone. Even though it is hard and stressful, I just enjoy those times.”

But the primary storyline belongs to Lowry. Taking a four-stroke lead into the final round of the U.S. Open is stressful, but it's also a great position.

He has proved he can handle the pressure for 54 holes. Now he must prove he can do the same for the final 18 if he is to pick up the first major championship of his career.