Willett followed a double bogey on the opening hole of his second round with an eagle and six birdies to complete a superb 66, beating his previous tournament best of 67 set in the final round of his dramatic triumph in 2016.
Spain's Jon Rahm was one shot off the lead and facing a short birdie putt on the 13th when play was suspended in the fading light, a legacy of the lengthy weather delay on Thursday morning.
Tweet of the day
Dustin Johnson named "sandwiches" as his favourite Masters tradition on Tuesday and with Johnson three shots clear at one point on Friday, one Twitter user imagined the world number one's Champions Dinner menu.
Quote of the day
Phil Mickelson has never been backwards in coming forwards and the 50-year-old had a typical response to a query about his driving.
Shot of the day
Australia's Cameron Smith took on the tricky pin position on the 15th and produced a stunning approach to set up a tap-in eagle.
Round of the day
Danny Willett recovered from a double bogey on his opening hole to card a superb 66, the 2016 champion's lowest ever round in the Masters.
Statistic of the day
Soft conditions following Thursday's rain meant Augusta National had fewer defences than usual and the players took full advantage.
The second hole continued to be the easiest on the course, the downhill par five playing to an average of 4.446 after giving up one eagle and 49 birdies.
The first hole displaced the 10th as the toughest, playing to an average of 4.273 after giving up just six birdies and causing 24 bogeys and three double bogeys.
On the up
The prospects of an English winner after Danny Willett, Tommy Fleetwood and Justin Rose all ended the day two shots off the lead.
On the slide
Bryson DeChambeau's mood after the US Open champion somehow lost a ball in the rough to the left of the third fairway, much to his frustration.