"High up there with the best wins I've had", Molinari said.
After a birdie on the par-five 16th hole, Fitzpatrick parred his final two holes to get his best finish on Tour. His putt on No. 18 capped a 12-under weekend where he gained more than four strokes on the field on the greens.
"I'm playing well, I'm getting myself into contention every week", said the Co Down man who will play just twice more before he seeks that elusive Masters victory at Augusta National in five weeks.
After back-to-back 70s in the opening two rounds he posted five birdies and dropped no shots in a 67 on Saturday to move to nine under par.
This time, he was in good position just one shot behind Fitzpatrick. He played in the final round of the BMW PGA Championship at Wentworth tied with McIlroy, closed with a 68 and won by two.
"I was saying before, it's probably my best putting round ever".
"I was the first to make it with the flag in", Molinari said with a big smile, alluding to a new rule that allows the flag stick to stay in the cup with putts on the green. The frustration mounted for the world number 37 when he three-putted the last and finished eight under.
He all but sealed the win with a 44-foot birdie putt across the green at the last and although many of his nearest challengers still had several holes to play they faced a tough task to catch the leader and so it would prove.
2 people from Redding killed in Ethiopian Airlines crash
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"It's great, to do it here, to get it done here at this place knowing that my wife and the kids were watching back home, it's just a special, special one".
Sungjae Im, Tommy Fleetwood and Rafa Cabrera Bello finished in a three-way tied for third at nine under. I've seen so many putts on TV like that and to do it yourself it's really awesome.
His T6 finish with Wallace, Sung Kang and last week's victor Keith Mitchell is McIlroy's fifth consecutive top 10 on Tour. "The course was firm and fast [Saturday] and I knew it wasn't going to be easy for the guys in the lead, so I thought there was an outside chance". He would bogey his final hole to finish the week at two under, having given four shots back over the last two holes. If you were wondering how on earth Molinari would come up with an encore following his three victories worldwide last season and heroics in Paris, wonder no more.
The four-time PGA Tour victor came within a shot of the lead early in his round but a bogey at the par-4 9th started a poor run that included only one birdie, bogeys at the 12th and 17th, as well as a double-bogey six at the 15th. It turned out to be too much for anyone to catch him.
PGA Tour officials confirmed on Sunday that Tiger Woods will speak to the media at TPC Sawgrass on Tuesday, a sign that the 14-time major champion is hoping to give it a go at the Players Championship on Thursday.
"Yeah, it's a pretty iconic putt", said Molinari. "I think obviously confidence has to do a lot with it".
This was a first glimpse for America of the 24-year-old who last year became the youngest Englishmen since Sir Nick Faldo to win five times on the European Tour.