MEDINAH, Ill. — Justin Thomas had more stress than he wanted and answered with the shots he needed Sunday at Medinah to win the BMW Championship and claim the No. 1 seed going into the FedEx Cup finale.

Thomas watched a six-shot lead shrink to two in a span of three holes around the turn until he regained control with two great wedges, and two pivotal putts. One last birdie gave him a 4-under 68 and a three-shot victory over Patrick Cantlay, who gave him a battle to the end with a 65.

“I was really nervous today. It’s hard to play with a lead,” Thomas said.

The victory, the first for Thomas since the World Golf Championship at Firestone last year, gives him a two-shot lead starting the Tour Championship next week as the top 30 players in the FedEx Cup chase the $15 million prize.

The field will have a staggered start based on their position in the FedEx Cup, meaning Thomas starts at 10-under par.

The top 30 who advanced includes Lucas Glover, who went bogey-double bogey late in his round until finishing with a par to wrap up his first trip to East Lake in 10 years.

It will not include Masters champion Tiger Woods, the defending champion.