MIAMI (AFP) - Collin Morikawa, seeking a victory to become world number one, fired an eight-under par 64 to seize a five-stroke lead after Saturday's (Dec 4) third round of the Hero World Challenge.

The 24-year-old American made six birdies and an eagle chip-in to stand on 18-under 198 after 54 holes in the 20-man invitational hosted by Tiger Woods at the Albany resort in the Bahamas.

Four-time major winner Brooks Koepka, ranked 16th, shot 69 to stand second on 203 and join the reigning British Open champion in Sunday's last pairing.

A third-place pack on 204 included Norway's Viktor Hovland and Americans Patrick Reed, Daniel Berger, Sam Burns and Tony Finau with Scottie Scheffler on 205 and fellow American Bryson DeChambeau, the 2020 US Open winner, on 206.

Morikawa, who also won a major title at the 2020 PGA Championship, captured last month's DP World Tour Championship, becoming the first American to win the Race to Dubai.

Second-ranked Morikawa, who got engaged earlier in the week, can overtake Spain's Jon Rahm to reach the top of the rankings for the first time if he remains on top for another 18 holes.

Morikawa chipped in for eagle at the par-5 third and birdied the fourth but missed a four-foot birdie putt at the par-4 seventh.

He escaped a bunkered tee shot to birdie the par-5 ninth and grab the lead alone at the turn at 14-under.

Morikawa rolled in an eight-foot birdie putt at the par-4 10th and followed with a four-foot birdie putt at the par-5 11th for a three-stroke lead at 16-under.

Morikawa added birdies at the 14th and par-5 15th - giving him three birdies and an eagle on the par-5s Saturday.

At 18, Morikawa blasted out of a greenside bunker to three feet and saved par to cap only the fourth bogey-free round of the week.

Burns was four adrift before a closing double bogey while Finau and Berger were five back before making bogeys at 18.