Collin Morikawa is close to overtaking Jon Rahm as the world's top golfer after opening up a five-stroke lead ahead of the final round of the Hero World Challenge.

A victory for the two-time major winner in the Bahamas will see him follow Tiger Woods, Rory McIlroy and Jordan Spieth in becoming the fourth person to become world number one before turning 25.

Morikawa started Saturday's session at Albany Golf Club as one of three players a stroke behind leader Bryson DeChambeau after an unfortunate bogey on the final hole on day two.

DeChambeau's lead quickly evaporated with a bogey on the opening hole, however, and the American struggled with three more bogeys on the back nine to finish one-over-par for the day as he slipped down to ninth.

Open champion Morikawa took full advantage by firing an eight-under 64 in a round that included six birdies and an eagle chip-in on the par-five third.

Morikawa, who last month became the first American to win the Race to Dubai with a victory at the DP World Tour, is now 18-under after 54 holes on the 20-man field.

Fellow American Brooks Koepka shot 69, his only blemish a double-bogey on the par-three eighth, to move into second place behind Morikawa.

Daniel Berger dropped two shots on the final three holes and joins Patrick Reed, Viktor Hovland, Sam Burns and Tony Finau in a tie for third, six strokes behind Morikawa.

The performance of the day belonged to Harris English thanks to his 10 birdies, though it was not quite a blemish-free round as he dropped a shot on hole one.