OLD WESTBURY, N.Y. — Jordan Spieth needed only three holes to leave a strong cast of challengers wondering what it's going to take to catch him in the Northern Trust.
Spieth ran off three straight birdies on the back nine at Glen Oaks Club and finished with a pair of pars for 6-under 64, matching the low score of the tournament and building a three-shot lead over Dustin Johnson on Saturday.
It was the second straight day in the opening FedEx Cup playoff event that Spieth filled his card with birdies on the easier back nine. He shot 30 on it Friday and 31 Saturday.
Johnson stuffed his approach into 4 feet on the 18th hole for a birdie and 67 to get into today's final group with Spieth.
Spieth was at 12-under 198, and his reputation — even for a 24-year-old in his fifth year on the PGA Tour — is as daunting as the size of his lead. Spieth has a 9-5 record with at least a share of the 54-hole lead, winning nine of the past 10 times.
"Ten except for one hole," he said, smiling, referring to the quadruple bogey he made on the 12th hole at Augusta National that cost him the 2016 Masters.
Paul Casey, who seems to play his best golf this time of the year, and defending champion Patrick Reed each had 66 and were next in line at five shots back, along with Jon Rahm (67) and Matt Kuchar (68).
Missing from the mix were Jhonattan Vegas and Rickie Fowler, who started the third round as part of a four-way tie for the lead with Spieth and Johnson. Vegas shot 72 to fall eight shots behind. Fowler, playing with Spieth, opened with five bogeys in six holes and fell 10 shots behind after 74.
"A five-shot lead requires two things: a really good round from whoever is coming from behind and the leader to stumble a little bit," Rahm said. "And Spieth is not known for being one to stumble."
That's partially correct.
Spieth would love nothing more than a boring round today.
"I don't expect it, though," he said.
LPGA: Tour rookie Nicole Broch Larsen birdied two of the last three holes for 5-under 66 and a share of the lead with Mo Martin (67) in the Canadian Pacific Women's Open at Ottawa. At 10-under 203, they had a one-shot lead over second-round leader In Gee Chun (70). Brooke Henderson, from nearby Smiths Falls, Ontario, shot a course-record 63 and was 7 under. Seminole's Brittany Lincicome (71) was 6 under.
Champions: Jerry Kelly shot 6-under 66 to take the lead alone at the Boeing Classic in Snoqualmie, Wash. The first-round co-leader had a three-shot lead at 13-under 131 over Billy Mayfair (65) and Jerry Smith (66). First-round co-leader David McKenzie (73) was 6 under.