Adam Scott and Louis Oosthuizen closed off round one of the WGC-HSBC Champions with a shared lead of 65 at Mission Hills in Shenzhen, China.
South African Oosthuizen set the clubhouse target following a 14-foot birdie putt on the ninth and finished his opening round seven-under-par.
Scott, who ruined his chances of Open glory in July by recording four bogeys on the back nine, edged closer to his opponent over an hour later by claiming back-to-back birdies.
Ireland's Shane Lowry sits just behind on six-under with an overall 66, with American duo Bubba Watson and Phil Mikelson on the same score.
