World No 24 Bo van Pelt prevailed in the battle of the Americans to win the inaugural $2 million Perth International at Lake Karrinyup on Sunday.
Van Pelt started the day one stroke clear of countryman Jason Dufner, and two ahead of 20-year-old Argentine Emiliano Grillo.
Grillo, who led by as many as five strokes early in his third round, failed to keep the fire burning on Sunday, shooting a tame two-over 74 to leave van Pelt and Dufner to fight it out for the trophy.
World No 10 Dufner had his moments, chipping in for birdie on the par-five seventh, and also sending a beautiful approach shot to within 15cm of the hole at the par-four 14th.
But van Pelt was up to the challenge, carding a four-under 68 to finish 16-under for the tournament and two clear of Dufner.
Spain's Alejandro Canizares finished third at 11-under, with Kiwi Michael Hendry two strokes further back in fourth.
Grillo dropped two shots on his final three holes to finish at eight-under, but his equal fifth-place finish should be enough for the world No.516 to retain his European Tour card for next year.
Defending Australian Open winner Greg Chalmers was in the hunt for a top-three finish, but a double-bogey on the 16th and bogey on the 17th saw him tumble to 10th at seven-under.
"I wish I could have one swing back - the tee shot off the 16th when I made a double bogey," Chalmers said after shooting a one-under 71 in his final round.
"I figured out after nine holes today I was never going to win the tournament.
"But I was in a good position to have a top-three or top-five position, and I blew it over the last few holes."
Former world No.3 Paul Casey produced one of the best rounds of the day, shooting a five-under 67 to make a surge up the leaderboard.
But his three-over 75 on Friday cost him any real chance of victory, with the Englishman forced to settle for a tie for fifth at eight-under along with Grillo, Scott Jamieson, Rhys Davies and David Howell.