US Open Leaderboard 2016: Updated Scores and Standings from Sunday at Oakmont

Shane Lowry entered this week with one PGA Tour victory on his resume. He'd never finished any better than ninth in a major tournament and was cut in three of his last five.

After three sterling rounds at Oakmont, Lowry has 18 holes to hold a four-stroke lead and win his first U.S. Open. The Irishman finished his third round early Sunday morning, finishing up a back-nine 32 to go five under on the day. He sits at seven under overall, four strokes ahead of Andrew Landry and Dustin Johnson.

"That's one of the best rounds of my career right there," Lowry said, per the Associated Press (via ESPN.com). "A 65 on this golf course, against this field, is pretty good."

Lowry's seven-under score through 54 holes is the best ever in an Oakmont U.S. Open. Angel Cabrera won the 2007 U.S. Open at five over, and there has never been a winner to finish better than five under at the Pittsburgh course. Johnny Miller in 1973 and Ernie Els in 1994 share the record.

While not a household name, Lowry has game. He entered 2016 as the world's 21st-ranked player before struggling through most of the year. His only top-10 finish came at the Phoenix Open in February and he's only missed two cuts. Tournaments have mostly just been filled with Lowry scraping above the cut line before finishing his weekend rounds by lunch.

Lowry would have the fewest wins by a U.S. Open winner since Graeme McDowell won his first PGA tournament at Pebble Beach in 2010. He said he plans on following the same strategy he's taken through the first three rounds to close it out, per Kyle Porter of CBS Sports:

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I think it's just the same as I've been doing all week. Just trying to hit the ball down the fairway and hit it on the green. Try and make pars. Every par you make, kind of put it in your pocket and get on to the next tee. If you get yourself out of position, you've got to make bogey. And if you get yourself in a good position, then you've got to take your opportunity and make a birdie.

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Sitting in a tie for second are a pair of players with vastly different resumes.

Johnson is, perhaps inarguably, the best player to never win a major. This will likely be his fifth top-10 finish in his last six major championships, and the 31-year-old has 11 top-10s in his career coming into this week. Since returning from his 2014 leave of absence, Johnson has been a renewed player, and currently sits sixth in the world rankings.

This fourth-round Johnson becomes the hunter a year after being the hunted. His late failures last year allowed Jordan Spieth to come back for his second major of 2015 and further solidified Johnson's status as a great who couldn't quite get the job done.

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"The longer it goes, the more challenging it becomes. ... The more it's discussed, the more you start thinking about it," Phil Mickelson, a player who endured a long drought before his first major title, told Ian O'Connor of ESPN.com. "The challenge is really on Friday and Saturday nights, when you have opportunities and you start putting that self-imposed pressure (on yourself), because then you never play free."

Johnson is tied for second with Landry, who came into this week ranked No. 624 in the world. Tiger Woods is still ranked higher than Landry. Yet here we are, with Landry holding over with rounds of 71 and 70 after his first-round 66. He had missed six cuts in 11 PGA Tour events before this week, never finishing better than 41st.

Barring a complete collapse, Landry's going to walk away with the biggest check of his pro career and a new best finish.

Lee Westwood and Daniel Summerhays are tied for fourth place at two under. Nevertheless it would take a huge collapse from Lowry for anyone to get within striking distance for taking the year's second major.