Willett reached a career-high of ninth in the world after claiming his first major title at Augusta National in 2016, but had slumped outside the top 450 earlier this season after suffering numerous injuries and a loss of form.
A missed cut in the French Open was his ninth in 12 events this season, but the 30-year-old from Sheffield bounced back to finish sixth in the Irish Open and was also in contention a week later in the Scottish Open at Gullane.
Those performances mean Willett will head into the Open Championship at Carnoustie with renewed confidence, especially as he believes his physical problems - the most recent being a knee injury in Italy - should be a thing of the past.
"You try and gain confidence from the process of what you're doing and how hard you're working and all those things but it is a massively results-driven game and it's always nice to see results from the things that you're putting in," Willett told Press Association Sport.
"When you know the process is good and you don't see the results, it does annoy you and you're wondering why, what you're doing wrong and what you need to improve on.
"Foles [coach Sean Foley] has been great, guiding you in the right direction, telling you the right things at the right time and we're in a nice place. The body is in in a great place now.
"The back hasn't been an issue now for eight months. I changed everyone in my team and first thing we did was say 'I need to get fit'. I want to play this game for 20-odd years and even now standing here, I'd take the 18 months of s*** that I have had in order for me to play well over the next 20 years.
"I'm in a fortunate position where I've got a lot of exemptions so I was in the position where I could do that. And I guess in hindsight the major injuries where I was struggling to get out of bed in the morning and all the painkillers I was taking, it's actually probably a good thing for me.
"It told me 'look, you need to change something here'. Even after winning the Masters and everyone is thinking you are going to ride the crest of this wave, I was still taking six painkillers a day and trying to manage a body that wasn't liking what I was doing.
Pinnacle | Willett dons the Green Jacket at Augusta National in 2016 (Getty Images)
"It's been a very trying 18 months but I really do feel that the body now is in a place that is really good and manageable. There's not really an end to the swing stuff. You're always trying to change and get better.
"But the main thing for me is to be able to roll out of bed, not have to pop painkillers and be able to pitch up at the first tee and play some golf."
Willett is not about to get carried away and start thinking about a second Ryder Cup appearance in Paris in September, especially as he is a lowly 56th in the qualifying standings.
But he did play alongside European captain Thomas Bjorn and his predecessor Darren Clarke for the first two rounds in Ireland and joked: "I'll make sure I'm in the back of his mind!
"We had a good laugh about it actually. I've known Thomas for a lot of years and played under Darren [at Hazeltine]. They saw me when I first came on Tour, saw me win at the Masters and have obviously seen the downturn in form and what it does to you mentally.
"They are very supportive people in what I'm trying to do."