Louis Oosthuizen was in a share of 11th after his opening one-under-par 69 in the first round of the LIV Golf-Chicago event at Bolingbroke Golf Club in Illinois.
Oosthuizen started on the second hole in the shotgun start, and made birdie there. He dropped a shot on the next. It was pars all the way until he dropped another shot on the 12th, and yet another on the 13th. He got things back on track with birdies on 15 and 16, and again on his closing hole, the first.
Brooks Koepka led on eight-under without dropping a shot. He was four clear of Paul Casey and five ahead of Anirban Lahiri. There were seven players on two-under-par in a share of fourth.
Dean Burmester had a level-par 70 for a share of 19th, while Branden Grace, who is fighting to retain his place in LIV Golf after a poor year, had a one-over 71 for a share of 21st. Charl Schwartzel was on two-over in a share of 33rd.