AUSTIN, Texas (AP) -- Jordan Spieth had another stress-free day in the Dell Match Play, avoiding some of the drama the 18th hole provided Thursday.
Spieth again built a big lead and lost only one hole in a 5-and-4 victor over Victor Dubuisson of France. He has played 30 holes in his two victories, and needs only to halve his match Friday against Justin Thomas to reach the round of 16 at Austin Country Club.
"When you're 3 up and you're striking the ball well on a windy day with a difficult golf course, it's difficult to come from behind," Spieth said.
Jason Day ended any suspense about his back injury - first by showing up, then by hitting his opening drive to 12 feet on the 381-yard first hole. He was headed to a comfortable victory over Thongchai Jaidee, which puts him in the same position as Spieth.
For others, the 18th hole was pivotal.
Phil Mickelson was all square on the last hole when Daniel Berger drove left next to a rock structure that forms the 10th tee box. Berger struck the rocks before his club reached the ball. He dropped the club, grabbed his left wrist and looked over to Mickelson to concede the match.
"That's happened to me before, not the injury, but swinging over the top of it or misjudging where the obstacle is," Mickelson said. "It happens. So I was just watching if the ball was struck and it wasn't. He hit the rock on the downswing. And hopefully his wrist is OK."
Mickelson moves on to a winner-take-all match against Patrick Reed. Berger was among those eliminated and contemplated whether to play Friday, especially with his first Masters appearance only two weeks away.
Sergio Garcia was poised to win his second straight match until Ryan Moore knocked in a 25-foot putt from behind the 17th green to square the match, and then hit wedge to a foot on the final hole for a 1-up victory.
"Match play is just crazy," Moore said. "You just never know what's going to happen."
Patton Kizzire, one of three PGA Tour rookies in the 64-man field, was 1 down to Bubba Watson playing the 18th hole when he hit his approach to 5 feet and made it to halve the match. If he missed, he would have been eliminated. Now he can win the group if he beats Emiliano Grillo on Friday and J.B. Holmes beats Watson.
At least 15 players were eliminated with one more day of round-robin matches.
Spieth knows the course better than anyone from his three semesters at Texas - the Longhorns used to stage qualifying on the course. He also faces more attention as the local favorite, not to mention the No. 1 player in the world.
So far, he has played some of his best golf since he won at Kapalua to start the year.
"My swing has been coming around," he said. "I've been working hard on it for the last month or so. Really started showing signs of that work this week."
He escaped with a halve on the opening hole after Dubuisson hit a pair of weak putts, a bad sign for the Frenchman. Dubuisson three-putted to lose the second hole, Spieth holed a 10-foot birdie on the next, and he seized control on No. 5. With Dubuisson about 10 feet below the hole, Spieth floated a wedge from an awkward distance (40 yards) to within 5 feet. He made, Dubuisson missed, and Spieth was on his way.