World numbers one and two Rory McIlroy and Tiger Woods both suffered defeats on the first day of the Turkish Airlines World Golf Final.
First round losers: Tiger Woods and Rory McIlroy
Ulsterman McIlroy, playing in his first event since the Ryder Cup nine days ago, was below his best in his match against Matt Kuchar and lost by six strokes, while Woods finished two strokes behind 2011 Masters champion Charl Schwartzel.
Despite making two eagles in the front nine, McIlroy (76) was three shots behind Kuchar (70) after the American birdied the tenth.
Even though the world's best player seemed to still be in contention with four holes to go, he fell apart in dramatic fashion, going triple bogey, double bogey, double bogey from 15-17 to slump from two-under to five-over.
Schwartzel (68) edged ahead of Woods (70) early in their match, but the former world number one pulled level with the South African after birdies on the 16th and 17th, but a loose approach shot into a bunker forced him into a dropped shot, handing victory to Schwartzel.
In the other matches that took place on the day, Justin Rose (71) was below his best but nevertheless beat American Hunter Mahan (75), who didn't make a single birdie on the day, while Lee Westwood (72) made par on the final hole to beat Ryder Cup foe Webb Simpson (73).
Each competitor play three matches in the group stage, after the two top placed players in each group advance to the semifinals and final.
The winner of Group One (McIlroy, Woods, Kuchar, Schwartzel) will then play the runner-up of Group Two (Rose, Mahan, Westwood, Simpson) and vice versa on Thursday.
The final will be on Friday.
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