Jason Day, who exhibited apparent back pain on the last hole of Wednesday's round at the WGC-Dell Match Play, showed no signs of lingering pain during Thursday's group play at Austin Country Club in Texas.
Day, coming off a victory in the Arnold Palmer Invitational, defeated Thongchai Jaidee of Thailand, 5 and 3, and is now 2-0 heading into the final round of group play. Day's round featured six birdies and an eagle after driving the green on the opening hole, a par 4.
"It's not too bad," he said of his back issues. "Yesterday it was definitely sore. I mean, I've had it before. I know what the protocols are for me when these things pop up. It's a disc. When it gets inflamed the facet joints lock up and then everything goes into spasm and I can't move and it's really difficult to play golf."
Jordan Spieth, the No. 1 ranked player, continued his run of dominance with a 5 and 4 win over France's Victor Dubuisson. Spieth is now 2-0 in group play heading into Friday's match against his good friend Justin Thomas.
Rory McIlroy, after winning because of a shank from Thorbjorn Olsen on the 18th hole on Wednesday, bounced back to defeat Smylie Kaufman, 3 and 1, to move to 2-0.
Phil Mickelson edged Daniel Berger, 1 up, while fellow group member Patrick Reed defeated Matthew Fitzpatrick, 4 and 3. Mickelson and Reed are each 2-0 and will play each other on Friday to see who advances to the weekend.
Rickie Fowler halved his match with Scott Piercy, moving to 0-1-1 and needing several things to go right on Friday to advance.
The easiest match of the day went to Zach Johnson who beat Martin Kaymer, 8 and 6.