Kevin Na kept his cool with a red-hot putter to hold off fellow American Nick Watney and claim his first PGA Tour title with an emotional two-shot victory at the Las Vegas Open on Sunday.

South Korea-born Na rolled in a 43-footer to birdie the par-three 17th before parring the last for a six-under-par 65 and a 23-under total of 261 at the TPC Summerlin.

The 28-year-old, who had been winless in his previous 210 PGA Tour starts, threw both arms skywards in celebration before removing his cap and embracing his caddie.

Oh wow, a tearful Na said greenside after being told he had finally triumphed in his 211th career start. I went through a lot. I'd have nightmares finishing second.

I used to tell my mother: 'As hard as I work, when I am going to get my first win?' People said they believed in me more than I think I believe in myself, especially Kenny my caddie.

Every time he was there for me and he believed in me.

Tied for the lead overnight with Watney, Na was briefly caught at the top by his playing partner with four holes to play before he tightened his grip on the title with birdies at 15, 16, and 17.

World number 11 Watney, bidding to become the PGA Tour's first three-times champion this year, had to settle for second place after closing with a four-birdie 67.

Americans Tommy Gainey and Paul Goydos both signed off with 68s to share third place at 18 under.

A NA-WATNEY DUEL

For most of Sunday's final round, however, the tournament came down to an effective head-to-head between Na and Watney, the two overnight leaders.

Na made a red-hot start, birdies at the first and second holes putting him two strokes clear at 19 under.

Though Las Vegas resident Watney cut that deficit to one with a long-range birdie putt at the third, Na restored his two-shot cushion by sinking a 20-footer from just off the green at the par-four fourth.

Na made his first mistake of the day with a bogey at the sixth, after missing the fairway to the left off the tee, and dropped back into a tie for the lead with American Tim Herron at 19 under.

Herron, a four-times winner on the PGA Tour whose most recent victory came at the 2006 Colonial Invitational, had birdied four of the first seven holes before losing momentum over the closing stretch on his way to a 69 and joint fifth.

Na, however, immediately bounced back with a birdie at the seventh before picking up another shot at the par-five ninth after reaching the green in two and two-putting.

Two ahead at the turn, Na was briefly caught by Watney when he bogeyed the par-three 14th after failing to get up and down from a buried lie in a greenside bunker.

The long-hitting Watney had rolled in a 15-foot birdie putt at the par-five 13th to get to 20 under overall.

Once again, though, Na regained control, sinking a three-footer to birdie the driveable par-four 15th before following up with a two-putt birdie at the par-five 16th to lead Watney by one.

He never relinquished his grip as he finished birdie-par to triumph by two strokes.

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