Rory McIlroy began his quest for the highest top prize in golf with an eight-under-par 64 to lead after the first round of the Shanghai Masters.
The 30-man invitational event is not sanctioned by any of the major tours but carries a top prize of £1.25m.
McIlroy's bogey-free round earned him a one shot lead, while his playing partner and former ISM stablemate Lee Westwood carded a 69.
Westwood described as "bizarre" McIlroy's decision to leave ISM.
There are no ranking points on offer at the tournament, which is being run by the International Management Group, but a total purse of $5m (£3.1m) has persuaded many of the world's top players to participate, with 16 from the USPGA Tour.
Much discussion centred on a reported coolness between McIlroy and Westwood following the Northern Irishman's decision to join compatriot Graeme McDowell at the Dublin-based Horizon group.
"I've come here to talk about my 64," McIlroy said when asked about his move and claims of a rift with Westwood.
Westwood, whose eagle putt from the fringe on the edge of the 13th green stopped an inch from the cup, was able to offer McIlroy advice on a free drop in the lip of a bunker on the 15th.
He was less impressed by the camera-happy Chinese spectators, however, quipping: "If you ask me, I'll smile next time." The 38-year-old world number two even resorted to some impromptu Chinese lessons to ask the fans to desist in their own language.
McIlroy, who had five birdies on the back nine at the Jack Nicklaus-designed course at Lake Malaren Golf Club on the outskirts of Shanghai, added: "If I can play as solidly for the next three days as I did today, I feel as if I'll be very difficult to beat."
The 22-year-old is one ahead of American Hunter Mahan, and is one of 10 major winners in the field.