'This is huge for me,' said Daly-Donofrio, who pocketed $130,000 for the win. 'I can't believe this happened. I won it and have another three-year exemption on tour.'
Daly-Donofrio only got an invitation into the field this week because tournament officials relaxed the qualification process. Her only other win on tour was in 2001 and officials decided to open the tournament to Hall of Famers and winners from this season and the last three years.
Diaz birdied her final two holes to polish off a 3-under 69. Her second-place finish got her enough money to get into the field next week at the ADT Championship, which is reserved for the top-32 on the LPGA Tour money list. Wendy Ward, who tied for 16th, collected enough money to grab the final spot next week.
Reigning Women's British Open champion Karen Stupples and Candie Kung each bogeyed the final hole Sunday for rounds of 1-under 71. The duo shared third place with Sophie Gustafson, who carded an even-par 72, at 14-under-par 274.
Daly-Donofrio brought a three-shot lead into the final round and parred her first two holes to maintain her advantage. At the par-4 third, Daly- Donofrio found the fairway then hit a 9-iron from 132 yards. The ball landed 15 feet short of the hole, but rolled in for an eagle-two and a five-stroke lead.
'I thought maybe I can't do anything wrong today,' admitted Daly-Donofrio, referring to what she thought after the improbable eagle. 'That was a bonus. It was great.'
Daly-Donofrio parred her next three holes before she sank a 20-footer for birdie at the seventh. Gustafson, her playing partner on Sunday, made things a bit more interesting with a birdie at the seventh and a 5-foot birdie putt at No. 9. Daly-Donofrio had 45 feet for birdie at the ninth, but left her putt 15 feet short. She calmly drained the par-saving putt to maintain a three-shot edge.
Gustafson found serious trouble at the par-5 13th. Her drive went well into the trees on the right side and after several struggles, was in the fairway hitting her fifth shot from 216 yards. That landed in the front bunker, where she got up and down for a double bogey.
Daly-Donofrio had a five-shot lead and coasted. She hit a terrible drive at the 15th and missed the green short with her second. Daly-Donofrio's chip hit the hole and rolled 6 feet past, where she converted the par putt.
Diaz got within five as Daly-Donofrio reached the last. Daly-Donofrio's drive split the fairway, but her approach came up so short and left, Daly-Donofrio laughed at the approach. She chipped 45 feet right of the flag, then two-putted for bogey.
'I hung in there and putted really well again today,' said Daly-Donofrio. 'Everybody in this field are tournament winners. I was a nervous wreck all day.'
The bogey on the closing hole cost Daly-Donofrio a piece of the tournament record. Se Ri Pak posted a 268 in 2002, but Daly-Donofrio recorded her second victory on tour to go along with the Betsy King Classic in 2001.
Daly-Donofrio came into the event 84th on the money list with only one top-10.
'It's been a grind. I've fought for every single dollar I've made this year,' said Daly-Donofrio. 'It was really a tough year. I figured this week I had nothing to lose. I'm used to finishing last here and anything I did was going to be better than that.'
Hee-Won Han fired a 5-under 67 and finished alone in sixth at 13-under-par 275. Cristie Kerr (69), Karrie Webb (70) and Carin Koch (70) shared seventh place at minus-8.
Liselotte Neumann posted a 2-under 70 and tied for 10th place with Lorie Kane, who carded a 1-over-par 73 on Sunday. The pair was knotted at 7-under-par 281.