McDowell won the US Open at Pebble Beach in 2010 and claimed the decisive point in Europe's Ryder Cup victory at Celtic Manor a few months later, as well as victory in the Wales Open on the same course earlier in the season.
The 33-year-old Northern Irishman also won the Andalucia Masters in October of that year, his last European Tour title until securing the Volvo World Match Play Championship by beating Thongchai Jaidee in the final at Thracian Cliffs in Bulgaria.
And the world number seven believes Sunday's triumph, coupled with his victory in the RBC Heritage last month and third place in the WGC-Cadillac Championship at Doral in March, means he is on top form ahead of this week's BMW PGA Championship and June's US Open at Merion.
"I've got one event now before the US Open. You could say I'm in the form of my life going into an event in which certainly my record kind of speaks for itself," said McDowell, who finished joint second at Olympic club last year, 14th in 2011, won in 2010 and was 18th in 2009.
"I feel like I'm a substantially better player than I was three years ago. I feel like I've learned a lot from this process that I've gone through the last two and a half years, winning the US Open, getting comfortable with deserving that US Open, getting comfortable with the player I was trying to become, acclimatising myself to being in the top 10, 20, 30 in the world, a new status in the game.
"Number one scrambler on the PGA Tour this year has been a telling stat. Last year I'll be the first to admit that my short game was not good and cost me probably the US Open (he finished one shot behind winner Webb Simpson).
"Hilton Head (for the RBC Heritage) was probably the best I've ever felt down the stretch in a golf tournament, just believing I can win.
"I'm feeling more experienced, I feel like I'm learning all the time. I'm comfortable on and off the golf course at the minute. I'm happy with what I'm doing technically, I'm certainly happy with what's ahead of me this year, getting married and settling down and doing all these good things in life which I feel adds to a stable mind on and off the course which has worked well for me this season."
McDowell travelled to Wentworth after a tiring week at Thracian Cliffs, where he sealed a 2&1 victory over Jaidee on his 99th hole of the tournament.
But he hopes paying attention to his fitness will pay off in the BMW PGA Championship, an event in which he has missed the cut for the last two years and has just one top-15 finish in 10 attempts.
"I'm not going to sit here and tell you that I'm some kind of gym rat and I'm a specimen, far from it," McDowell added. "But there's no doubt I've looked after myself the last couple of years and have been making an attempt to be fitter and stronger, eat better and get myself into the kind of shape that's going to carry me through a 36-holer.
"On Saturday I felt fantastic coming down the stretch, I really did. On Sunday I was starting to feel it a little bit but I looked across at my opponent and I saw that he was feeling it more than I was and I fed off that."