Former Masters champion puts a long run of bad form behind him to triumph in season-ending tournament
Danny Willett won his first title since the 2016 Masters at the DP World Tour Championship on Sunday, while Francesco Molinari became the first Italian to win the Order of Merit.
Willett, who has struggled for form and fitness since winning at Augusta National, fell out of the top 450 in the world rankings earlier this year, but was in great form at the Earth Course, where he shot 68 or better on all four days.
A final-round four-under par 68, which included a heroic par save from the creek that divides the 18th fairway, took him to 18-under par overall, two better than England's Matt Wallace (68) and American Patrick Reed (70).
Willett, 31, returned to the winner's circle after 953 days and said: "You never quite know when a win is around the corner and with all the things that have happened, I was never quite sure if it was going to happen again.
"We've battled long and hard through this season to come out at the end, regardless of what happened today, a better person and a better athlete. It’s a special place.
"It's been a lot of hard work. It's been tough and I'm just massively proud of myself and everyone that's been around me."
Defending champion Jon Rahm was among three players tied for the fourth place, two shots further adrift.
Molinari secured his Race to Dubai crown when Tommy Fleetwood (68), the only player who could have denied him the honour, failed to win the championship. The Englishman finished tied for 16th place at 10-under par.
Willett started the day tied for the lead with Reed at 14-under and an eagle on the second hole, followed by a birdie on the seventh, saw him take a three-shot lead going into the back nine as none of his rivals made any significant move.
Bogeys on the 10th and 12th brought a few other players into the mix, but he reeled off birdies on the 14th, 15th and 17th holes to enjoy a two-shot cushion over Wallace on the final hole.
Willett's tee shot with a three-wood rolled into the creek and the ball came to rest on the rocks. Instead of taking a drop, he hit his second shot from there, leading to a par that kept his two-shot margin intact.
Molinari, on becoming the new European number one and the first from Italy to do so, said it was an unbelievable feeling.
"Incredible," he said. "I'm going to have time to sit down and relax and really think back about the last few months. This morning on the first tee, the announcement of the winner of The Open Championship, Race to Dubai leader... doesn't sound real at the moment.
"I’m really struggling for words. It's more than I ever dreamed of achieving.
"I've seen guys that I think are better players than me not winning majors and not winning Order of Merits or Race to Dubai. To achieve those things, you know, in one single season, is just incredible."
India's Shubhankar Sharma, despite a disappointing final-round 80, won the Rookie of the Year honour ahead of Australia's Lucas Herbert. Sharma finished 28th in the Race to Dubai, 418,820 points ahead of Herbert, who was in the 47th place.