Northern Ireland's Rory McIlroy shot a seven-under-par 65 to take a two-shot lead in the first round of the World Golf Championships event in Shanghai.
McIlroy, 24, has struggled for form in 2013, failing to win a tournament.
He said: "It felt good to be out there and be in control of my golf ball. It's a great start, but it's only 18 holes."
Open champion Phil Mickelson birdied his 16th hole to share the lead but a quadruple-bogey nine at the next and a bogey at the last left him one under.
The American, who started on the 10th hole, twice found water on the par-five seventh, the second time after watching his ball land on the green and spin back more than 30 yards.
He then hit his approach to the ninth into a greenside lake as he ended with a 71.
Jamie Donaldson, of Wales, and Spain's Gonzalo Fernandez-Castano shared second place on five under par.
England's Justin Rose and Tommy Fleetwood, and America's Bubba Watson and Jordan Spieth are tied in fourth at four under par.
McIlroy, who sank eight birdies, is 62nd on the European Tour's Race to Dubai and needs to move into the top 60 this week to have a chance of qualifying for the DP World Tour Championship in November.
But his form has improved coming into this tournament and he beat Tiger Woods in an exhibition match earlier this week.
He added: "It's only one round of golf, but it's definitely the way I wanted, and needed, to start this week, keeping in mind that I obviously want to play myself into Dubai and try to pick up my first win of the season, as well.
"It's one of the best rounds I've played this season.
"I shot 64 at Boston, so that was a good round of golf. But this is probably better just because it was a little trickier conditions. There was a bit of breeze and you've got to play good golf to shoot seven under around this place."
The two-times major winner is just £3,400 behind Garth Mulroy in 60th place on the money list and victory in Shanghai would earn him £856,000.
Meanwhile, Tiger Woods's decision to miss the Shanghai event but accept a £1.25m appearance fee to play an exhibition match against McIlroy earlier this week has been criticised.
Giles Morgan, the global head of sponsorship at HSBC bank, the tournament sponsors, expressed his disappointment that Woods had missed the event for the second year in a row.
"For a meaningless game in China to take place only a few days before is disappointing. This tournament has to be bigger than the individual," he said
"Ultimately Tiger is a freelance agent, so it is his decision to do as he likes. I just feel that this tournament has an important role to take golf into an entirely different part of the world.
"Sponsors of our size deserve a modicum of respect for their investment."