Jordan Spieth rolled in a 50-foot birdie putt on the last hole to cap off a Saturday at the Hero World Challenge that was close to perfect.

Spieth opened with three straight birdies on his way to a 9-under 63 at Isleworth in Windemere, Fla., matching the best score of the tournament. That gave the 21-year-old Texan a seven-shot lead over Keegan Bradley and Henrik Stenson going into the final round.

"This is the best I've played in a 54-hole stretch," Spieth said.

He was at 20-under 196. Spieth said he has never been 20 under on any course through 54 holes, and he has never finished a tournament that many under par. That gave him a target for Sunday, when he goes after his second straight victory.

Spieth won six days ago halfway around the world at the Australian Open, where he closed with a 63 for six-shot victory.

Tournament host Tiger Woods was 20 shots behind and in dire need of his antibiotics taking effect. Woods lost his voice overnight and had nausea on the practice range and on the golf course. He felt slightly better at the end of his round when he made three straight birdies for a 69. He remained in last place.

Bradley made four straight birdies around the turn on his way to a 65. He will play in the final group with Spieth.

"I've got to shoot a low one and get some help from Jordan," said Bradley, who has not won in more than two years. "He's such a good player. I don't expect that."

Stenson, who played in the final group with Spieth on Saturday, recovered from a sluggish start with four birdies over his last eight holes for a 68.

- The Associated Press