Dustin Johnson produced a masterclass to equal the 54-hole score at the Masters, putting himself in prime position to win a maiden green jacket. (More Sports News)
The world number one was in a class of his own during a flawless seven-under-par 65 at Augusta National, leaving him at 16 under for the tournament – level with Jordan Spieth's score at the same stage in 2015.
Debutants Im Sungjae and Abraham Ancer join Australia's Cameron Smith as the nearest challengers, sitting four strokes adrift, while Dylan Frittelli is five back and Justin Thomas is 10 under.
Johnson has four top-10 finishes in his past four Masters appearances and it will take something special to deny the 36-year-old a second major title after his 2016 U.S. Open triumph.
A glorious front nine began with Johnson playing his opening four holes in four under, with a crunching approach at the par-five second leaving him a tap-in for eagle.
Three more strokes were gained prior to the turn, including draining a 38-foot putt at the fourth, while accuracy and crisp iron shots were hallmarks of Johnson's play on the way home, where he did the business on the par fives, birdieing both.
Johnson has previous for disappointments from promising positions in the majors but there have been few signs the chasing pack can play at the same consistently brilliant level to overhaul his commanding lead.
The 2019 PGA Tour Rookie of the Year Im had just one bogey in his round of four under, though, while Ancer also only dropped only one shot and Smith was boosted by a streak of three birdies between the 13th and 15th in a blemish-free round.
It was a case of what might have been for Thomas, who was three under through 11 holes but mixed four bogeys with two birdies from there to come home in disappointing fashion.
Jon Rahm struggled to get going and his even-par round included an ugly double-bogey at the eighth and another dropped shot at the last to leave him on nine under, level with 2018 champion Patrick Reed and Sebastian Munoz.
Rory McIlroy will be ruing a nightmare first-round 75 after following a 66 with a five-under 67 on Saturday.
The Northern Irishman was flying with five birdies and no bogeys through 12 before three-putting for bogey at 13 and regaining the stroke at the 16th.
At eight under McIlroy looks too far back to end the elusive wait to complete golf's grand slam. Brooks Koepka, Tommy Fleetwood and Hideki Matsuyama are on the same score.
The gap is even larger for reigning champion Tiger Woods, who sits 11 strokes off the pace after an even-par 72.
