Graeme McDowell was the first player to tee off in the Accenture Match Play Championship in Tucson - and the first player to make his exit.
For the second year running, Northern Ireland's former US Open champion lost to Korean YE Yang, this time by a 2&1 first round margin.
McDowell led after five holes on Wednesday, but Yang took control with birdies on the next two and then a par at the 476-yard ninth, where Europe's Ryder Cup hero double-bogeyed.
A six-foot birdie putt on the short 12th brought the gap back to one, but it was the closest McDowell could get and a superb approach to four feet on the 17th allowed the 2009 USPGA champion to close things out with a birdie.
"I'm playing good - today is a big mountain over," said Yang.
McDowell was out of the 64-man event before top two seeds Luke Donald and Rory McIlroy had even started against South Africans Ernie Els and George Coetzee respectively.
In the first of six all-European clashes, Scot Paul Lawrie led England's Justin Rose by two with four holes to play.
Rose struck first with a par on the 208-yard third, but three bogeys left him two down after eight and, even with a double bogey on the 10th, Lawrie maintained the upper hand.
Tiger Woods, beaten on the opening day by Thomas Bjorn last year, found himself two down after two to Spain's Gonzalo Fernandez-Castano.
Woods was the closer of the two on the first, but missed from seven feet after Fernandez-Castano - currently on course for a Ryder Cup debut in September - had holed from 10.
The Madrid golfer then carved his drive down the long second into the desert, but Woods followed him and had to play his second shot left-handed.
England's Robert Rock, conqueror of Woods and the world's top four in Abu Dhabi last month, trailed Australia's world number eight by
one after eight, while 2010 winner Ian Poulter was all square with Korea's Bae Sang-moon with eight holes remaining.
Their compatriot Simon Dyson lost the first two holes to Australia's John Senden and Open champion Darren Clarke bogeyed the long second and then hit his tee shot into the lake on the next to fall two down to American Nick Watney.
Lawrie's fellow Scot Martin Laird, meanwhile, was on level terms with big-hitting Spaniard Alvaro Quiros after eight.
The second player through to the last 32 was 20-year-old Japanese player Ryo Ishikawa - and he knocked out FedEx Cup champion Bill Haas, winner of the Northern Trust Open in Los Angeles on Sunday. Haas bogeyed the last to lose after standing three up with five to go.
Ishikawa will next play Lawrie, whose revival in the last two years continued with a last-green victory over Rose.
This is the Aberdeen player's first appearance in the event since 2003, but coming as it did only three weeks after his win in Qatar it was no surprise to see him making progress.
"I played solid," Lawrie said. "You want to play in these events, but there's no point playing if you come and get beat."
Rose's close friend Poulter, whose head-to-head prowess also brought him a title in the Volvo-sponsored version of the World Match Play in Spain last season, was in trouble when he bogeyed the 11th and 12th to fall two down, while Clarke and Dyson were four down before the turn and heading for big defeats.
Poulter suffered a first-round defeat for the second successive year. Last February it came at the 19th to Stewart Cink, but on this occasion he was well-beaten 4&3 by Bae, playing the first World Golf Championship of his career.
Woods came back to level with Fernandez-Castano, winning the fifth with a par and the seventh with a 40-foot birdie putt.
Thomas Bjorn, conqueror of Woods at the 19th last year, went 20 holes on his return to the tournament - and then lost when Italian Francesco Molinari chipped in for an eagle.
American Ryder Cup team-mates Dustin Johnson and Jim Furyk went two extra holes as well. Johnson, who had been three down earlier on, had to take a penalty drop from a bush there, but scrambled a par and won when his opponent three-putted.
