Young American Patrick Reed wore Tiger Woods red and he wore down Woods and a star-studded field to win the World Golf Championships-Cadillac Championship.

Reed became the youngest-ever winner of a WGC event at 23 years, seven months and four days, beating out Woods’ mark from his first WGC win back in 1999 by 26 days.

Despite taking his third career win, Reed was still in the shadows of Woods as the 14-time major champion was once again troubled by a back injury, putting his Masters preparations in jeopardy.

Reed was in control for most of the final round before some late flutters, but his bogey on the final hole and score of even-par 72 for a four-under total was enough for a one-shot victory over Welshman Jamie Donaldson (69) and American Bubba Watson (68), the only other players in red figures.

He earned a mammoth $US1.53 million ($A1.7 million) prizemoney cheque.

“I believe I have proven myself, Reed said.”

“I was hitting the ball so well this week and my putting was outstanding.”

Donaldson was the only real challenger, but a bogey on the final hole cost him his chance at victory.

Woods started the day three off the lead and in the penultimate pairing but struggled to a six-over 78 – the first time he has failed to birdie a single hole in a final round – as he finished at five-over in a tie for 25th.

A week after withdrawing from the Honda Classic with back spasms, Woods grabbed his back after several shots and could barely pull the golf ball out of the hole towards the end of the round.

His fitness a month out from the Masters is now in question.

Scott Hend was the leading Australian at four-over following a final round 71 and tie for 16th.

World No.2 Adam Scott’s 73 put his challenge for the top spot in the rankings on hold for at least another two weeks, leaving the Queenslander tied with Woods at five-over.

“I hit some poor shots and this course will penalise you,” Scott said.

“It wasn’t exactly the week I was looking for.”