Danny Willett won a tournament for the first time since becoming Masters champion in 2016 at the DP World Tour Championship, while Francesco Molinari wrapped up the Race to Dubai title.
Willett suffered a loss of form following his unexpected triumph at Augusta but held off the challenge of fellow Englishman Matt Wallace and reigning Masters champion Patrick Reed, with whom he shared the overnight lead, to come away with the victory.
The 31-year-old finished two shots clear of Wallace and Reed on 18 under par, despite bogeys at holes 10 and 12.
Molinari finished in a tie for 26th, but Tommy Fleetwood's failure to win the event - ending the weekend in 16th - was enough to see the Italian end the season as Europe's number one golfer.
Wallace joined Willett at the summit following the eventual winner's quickfire bogeys, but three birdies across the last five holes were enough to re-establish the cushion.
Reed struggled to keep pace with Willett on Sunday and was two over through the front nine.
He managed five birdies and a bogey after the turn but his efforts were not enough to elevate him back to the top of the leaderboard.
Jon Rahm, Adrian Otaegui and Dean Burmester were a further two shots adrift of Wallace and Reed in a tie for fourth.
Molinari's triumph brings to a close a season in which he won The Open and the BMW PGA Championship.
The 36-year-old was also one of the stars of Europe's victory in the Ryder Cup, forming a formidable pairing with Fleetwood that became known as 'Moliwood'.
Molinari, finishing the tournament six under par, becomes the first Italian to top the European Tour's money list.
"It's incredible," said Molinari. "Now 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 is the winner of The Open Championship, Race to Dubai leader, it doesn't sound real at the moment.
"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 Dubais. To achieve those things in one single season is just incredible."