Delasin, a local product of the San Francisco Bay area, cashed in on three birdies against no bogies at the Hiddenbrooke Golf Club to end at 11-under-par 277.
The 21-year-old second-year player on the LPGA Tour adds her trophy from this week to a pair of titles stemming from the 00 and 01 Giant Eagle LPGA Classics.
Four strokes back were tour superstars Karrie Webb and Se Ri Pak, each of whom shot 72s on Day 3 to end at 7-under for the tournament, while Kelly Robbins recorded a day-best 66 to finish in solo fourth at 4-under.
All in all, however, the week belonged to Delasin, who was met with hometown cheers all the way around Hiddenbrooke.
She birdied the first, the seventh, and topped off her round with a birdie-four at the closing par-5 18th.
For her efforts, she took home a check worth $154,000 in this limited field of 20 of the LPGAs best players.
As arguably the hottest golfer in the game presently, Pak might have given Delasin a run for her money, but came undone late in the round.
Just one shot back after the first nine holes of the day, the South Korean native and five-time winner for the year 2001 made four bogies over her final nine of the day to close with an even-par 72.
Webb, too, never could mount a charge, with a double-bogey at the par-4 8th sealing her fate.
After a third-round 68, defending champion Juli Inkster saw her chances fly away on Sunday with a 75. She finished at 1-under for the tournament.
Meanwhile, leading money winner on the LPGA Tour, Annika Sorenstam shot a similarly disappointing 74 to end at 2-over-par.
The LPGA Tour takes a week off next week and will return in South Korea for the inaugural Sports Today CJ Nine Bridges Classic.
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