(Reuters) - Local favorite Billy Hurley III, helped by a stunning chip-in on 15 and a monster putt at the 16th, clinched his first PGA Tour victory by three shots on Sunday at the Quicken Loans National in Bethesda, Maryland.

The 34-year-old American, a U.S. Naval Academy graduate who calls nearby Annapolis home, never relinquished his overnight lead in the final round at Congressional as he closed with a two-under-par 69 in the event hosted by Tiger Woods.

One stroke in front with four holes to play, Hurley chipped in from 35 yards to birdie the par-four 15th, and then sank a 27-footer at the par-five 16th to forge three ahead on the way to a 17-under total of 267.

Former world number one Vijay Singh, seeking his first PGA Tour win in eight years, fired a best-of-the-day 65 to finish second, with American Bill Haas (68) and Spaniard Jon Rahm (70) a further stroke back at 13-under in a tie for third.

It was a hugely emotional win for Hurley whose father, Willard Hurley Jr., went missing shortly before last year's Quicken Loans National before being located, but was then found dead the following month from a self-inflicted gunshot wound.

"I couldn't think of a better tournament for my first PGA Tour win so I'm thrilled to have gotten it done today," Hurley, ranked 607th in the world, told CBS Sports as he choked back tears.

"It's been a hard year, a really hard year, so it's nice to have something go well."

Prior to this week, Hurley had made just five cuts in 11 starts on the 2015-16 PGA Tour, his best finish a tie for 41st at the AT&T Byron Nelson last month.

On Sunday, however, he remained composed and mixed four birdies with two bogeys to keep his closest challengers at bay.

A stroke in front at the turn, Hurley increased his lead when his playing competitor Ernie Els ran up a double-bogey at the par-four 10th.

Though Hurley three-putted to bogey the 12th, he sank a clutch 10-footer to save par at the 13th before his sensational chip-in for birdie at the 15th, which prompted him to leap with delight before pumping his right arm skywards.

Rahm, the former Arizona State golfer who was the low amateur at last week's U.S. Open at Oakmont, ended a memorable debut as a professional after leading through 18 and 36 holes.

"I learned a lot," said the 21-year-old Spaniard. "I'm extremely honored to have played this week and to have played so good and had a chance to win it."

(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Andrew Both)