Viktor Hovland has emerged victorious after an extraordinary final round of the World Challenge in the Bahamas - with Collin Morikawa squandering a five-shot lead and the chance to become world No.1.

So wild was this final round of the year for golf's elite that Morikawa wasn't even a factor over the last hour at Albany Golf Club.

Hovland, who began the final round six shots off the pace, carded a closing 66, which included back-to-back eagles on the 14th and 15th, to secure his third title of 2021.

The 24-year-old Norwegian, who successfully defended his Mayakoba Classic title last month, bogeyed the last two holes to finish 18-under par.

Hovland was a shot clear of American Scottie Scheffler (66), who ran up a triple-bogey seven on the fourth but then picked up eight shots to briefly share the lead.

A hat-trick of birdies from the sixth and another on the 11th put Hovland in contention before he dropped his first shot of the day on the next.

However, he then holed a bunker shot on the short par-four 14th and followed it with another eagle on the par-five 15th to take command of the tournament.

A birdie on the 16th took the Ryder Cup star three shots clear and allowed him the luxury of two closing bogeys, with tournament officials also clearing him of a potential rules violation as he removed a loose impediment on the 17th green.

"I didn't think a win was going to be very possible but I know this golf course is tricky," Hovland told Golf Channel.

Tournament host Tiger Woods was on hand to watch the closing stages and Hovland added: "It's really cool being Tiger's event, that's incredible to be a part of and especially to win it."

Sam Burns (69), who was in a share of the lead before needing four attempts to chip up a steep slope on to the 14th green, shared third place with former Masters champion Patrick Reed (69) on 15 under.

British Open champion Morikawa, who would have replaced Jon Rahm at the top of the world rankings with a win, double bogeyed the fourth and sixth after losing a ball in dense bushes on each hole.

The 24-year-old, whose victory in the season-ending DP World Tour Championship ensured he became the first American to win the European Tour's money list title, duffed a chip on the ninth in a front nine of 41 and eventually signed for a closing 76 to finish in a tie for fifth with Justin Thomas (64) at 14 under.

To add to the sense of chaos, playing partners Jordan Spieth and Henrik Stenson had earlier been handed two-shot penalties for playing from the wrong tee box on the par-five ninth.

That led to a triple-bogey eight for Spieth and a seven for Stenson.

Spieth also carded another triple bogey, a double bogey and four birdies on the back nine in a closing 76 to finish last in the 20-man field, five shots behind 19th-placed Stenson (72).