“So we were at home last week and we were playing golf together and [Frankie] just said randomly: ‘Do you know what you’ve never done?’,” explained Fleetwood.
“‘You’ve never won a tournament and I’ve been able to run on to the 18th green’.
“All day today, I had in my mind: ‘Could I put myself in a position where I can actually make that moment happen?’.
“It’s just one of those little things that means a lot to me. That was really cool. That’s what I wanted to do all day.”
Fleetwood took control with four birdies from the seventh at the devilishly tight Delhi Golf Club, but it was a crucial par putt at the 11th that kept his round going.
“That one on 11 – I hit a couple of poor iron shots there on 11 and 12 – but that putt was big and I managed to just keep it going through the back nine,” said Fleetwood.
The 34-year-old put the title beyond doubt with a brilliant 25-foot putt for an eighth birdie of the day at the 17th to end Nakajima’s chances and the Japanese player had to settle for second.
The Englishman’s win followed him lifting the PGA Tour’s FedEx Cup order of merit in August.
He sealed that by finishing in the top four of the first two PGA Tour playoff events and then winning the season-ending Tour Championship for his maiden victory on the US-based circuit.
“There’s plenty of times where things haven’t gone my way,” said Fleetwood.
“But the last two tournaments [where] I’ve been in contention I’ve won, so maybe things are starting to even out a little bit.”
Fleetwood, the world No 5, was also the leading points scorer for the victorious European team at the Ryder Cup last month.
The inaugural $4 million event in India attracted a host of Ryder Cup players and star names to the historic Lodhi course at Delhi Golf Club, a green lung in the heart of the city studded with the ruins of Mughal-era tombs.
Ireland’s Shane Lowry had a final-round 68 to tie for third on 18-under par with England’s Alex Fitzpatrick and South Africa’s Thriston Lawrence.
Norway’s Viktor Hovland finished with a flourish, sinking a chip for an eagle three at the 18th to get into a three-way tie for sixth at 17-under.
Rory McIlroy struggled to get going on Sunday and a 71 that left him on 11-under and a share of 26th place.