UPDATE 1-Golf-American Gay coasts to record victory

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*Gay sinks monster eagle putt

*Clinches second PGA tour title

ATLANTA, April 19 (Reuters) - American Brian Gay, helped by a monster eagle putt at the second hole, charged to a scintillating 10-shot victory at the Heritage Classic in Hilton Head Island, South Carolina on Sunday.

Three ahead of the field overnight, Gay clinched his second PGA Tour title after closing with a sparkling seven-under-par 64 at the picturesque Harbour Town Golf Links.

Gay, who wore his trademark sunglasses all week, birdied three of the last six holes to post a record tournament total of 20-under 264, eclipsing the 265 set by American Loren Roberts in 1996.

"This feels great," Gay said in a greenside interview after making only two bogeys in four rounds on a narrow tree-lined course.

"It was just a phenomenal week, virtually mistake-free. I didn't see a leaderboard all day. We were just out there doing our thing. I just wanted to stay focused and I kept looking down."

Britain's Luke Donald closed with an eight-birdie 66 to share second place at 10 under with American Briny Baird (68).