Johnson fired an eagle and five birdies in a flawless third round of 65 to finish 16 under par – matching the 54-hole scoring record set by Jordan Spieth in 2015.
Australia's Cameron Smith, Mexico's Abraham Ancer and Korea's Sungjae Im are Johnson's nearest challengers on 12 under par, with Ancer and Im attempting to become the first players to win the green jacket on their tournament debut since Fuzzy Zoeller in 1979.
Johnson would be the first world number one to win the Masters since Tiger Woods in 2002, but is 0-4 when leading or sharing the lead after 54 holes in major championships.
Tweet of the day
Golf Channel analyst Brandel Chamblee details Rahm's unusual par on the 15th in round two, the Spaniard chipping in for par after opting not to go for the green in two, then hitting his third shot over the green and leaving his first pitch short of the putting surface.
Quote of the day
Bryson DeChambeau gives an interesting explanation for dropping shots on the 17th and 18th in his second round.
Shot of the day
Dustin Johnson's eagle on the second in round three was not captured by the television feed, but Matt Wallace's from earlier in the day is not a bad substitute.
Round of the day
Dustin Johnson began the third round tied for the lead but separated himself from the pack with a stunning 65.
Statistic of the day
Tiger Woods fans could dare to dream thanks to this strange coincidence, but his chances of a successful title defence disappeared with a third round of 72.
The par-five second hole was again the easiest, playing to an average of 4.533 thanks to two eagles and 29 birdies.
The 18th played as the toughest hole with an average of 4.383, yielding just four birdies, 21 bogeys and three double bogeys.
On the up
Dustin Johnson's chances of a second major title as he opened up a commanding lead.
On the slide
Jon Rahm's mood after the combustible Spaniard struggled to a third round of 72, which included a seven on the eighth.