Willett is 41 under par for his last 10 rounds on the Old Course at St Andrews after adding a 69 to his opening 66 to reach nine under par.
But while the vicar’s son from Yorkshire is rightly entertaining thoughts of becoming the first English winner of the Open since Nick Faldo in 1992, his mother Elisabet kept Willett’s feet planted firmly on the ground.
“I just had a text message off my mum saying ‘well done, you’ve made the cut’,” Willett told his post-round press conference.
“I’m sure there will be a few messages, I can feel my phone buzzing a little bit right now. But it might be a case of turning the phone off and having a little bit of quiet time.”
Play finally came to a halt at at 9.55pm with five-time champion Tom Watson bidding an emotional farewell while Dustin Johnson reached 10 under par with five holes remaining.
Paul Lawrie, 1999 champion, and Jason Day were eight under with six and seven holes left respectively.
Masters and US Open champion Jordan Spieth, playing alongside Johnson, was five under par after three birdies and three bogeys in 13 completed holes.
After play had been suspended for more than three hours in the morning due to torrential rain flooding the course, Willett carded birdies on the second, fifth and ninth to reach the turn in 33, before another birdie on the 10th gave him a three-shot lead as American Zach Johnson dropped shots on the 11th and 12th.
Three-putt bogeys on the 15th and 17th cut the gap to a single shot, but Willett took advantage of the downwind 18th to drive to the edge of the green and pitched to eight feet for a closing birdie.
“I looked at the leaderboard on 11 and knew we were three in front,” added Willett, whose best finish in a major is a share of 15th at Muirfield in 2013.
“It’s a childhood dream and looking up there it’s still a little bit surreal, but something I’m going to have to get used to, otherwise no point in being up there.
“You can’t really put it out of your mind but it’s pretty cool. Leading the Open is what you dream about.
“For Brits especially it’s the major you want to win and here at the ‘Home of Golf’ it’s a little bit more special.”
Willett won the English Amateur title in 2007 and defeated Rory McIlroy in the first round of the Amateur Championship the same year, racing five up after six holes before eventually sealing victory on the 17th.
Later that year he and McIlroy were on the same team in the Walker Cup as Great Britain and Ireland lost out at Royal County Down to an American side featuring Rickie Fowler, Billy Horschel, Dustin Johnson and Webb Simpson.
Willett, 27, claimed his second European Tour title in the Nedbank Challenge in South Africa last December, finishing with rounds of 65 and 66 to overturn a five-shot deficit to former world No 1 Luke Donald, and also reached the semi-finals of the WGC-Cadillac Match Play in San Francisco in May, losing to one of his playing partners at St Andrews, American Gary Woodland.
South Africa’s Jaco van Zyl hit the opening tee shot of the day at 6.32am and had a three-foot putt for birdie before play was suspended.
“They tried to squeegee the green, but water was rising quicker than they could get it away,” Van Zyl said.
“We had the option to putt out, but we all stopped, the hole was literally full with water.”
The lengthy delay meant the last group yesterday teed off at 7.27pm, meaning the round could not be completed on schedule.
But chief executive Peter Dawson said the R&A would not employ a two-tee start, which was implemented for the first time in Open history at Hoylake last year due to a bad weather forecast for Saturday.
“We do have the ability to go into Monday (the last time that happened was at Lytham in 1988), but we certainly hope not to,” Dawson said.
As play stuttered to a halt last night, Watson and playing partners Ernie Els and Brandt Snedeker opted to complete their second rounds in near-darkness.
The trio and their caddies – with Watson’s son Michael on his bag – paused on the Swilcan Bridge on the 18th for the traditional photograph before Watson was left to take the applause of the spectators who had stayed on to salute the popular 65-year-old.
A closing bogey, one of five in a row for a round of 80, barely mattered and was instead greeted with a loud cheer.