MEDINAH, Ill. — Justin Thomas opened with five straight birdies, added a pair of eagles and shattered the course record at soft, vulnerable Medinah with an 11-under-par 61 on Saturday, taking a six-shot lead into the final round of the BMW Championship.

Thomas hit a 5-wood to 2 feet for an eagle on No. 10, holed out from 180 yards with an 8-iron on No. 16 and made eight birdies, turning a tight race into a one-man show.

“I felt good about my game for a while, and you don’t know when something like this going to happen,” Thomas said. “We’ve all been talking the last couple of weeks that I’m due to have one, and it’s nice when it happens.”

And just like that, he was already thinking about Sunday.

Thomas was at 21-under 195, six shots ahead of Tony Finau (68) and Patrick Cantlay (67). He has a clear path to his first victory in a year, and it would give him the FedEx Cup lead going into the Tour Championship next weekend at East Lake in Atlanta.