Daniel posted a 4-under 68 to finish 72 holes at 13-under-par 275 and, in the process, put her name in the LPGA Tour's history book. At 46 years, eight months and 29 days, Daniel became the oldest player to win an LPGA Tour event.
'It's just fantastic. It's indescribable,' said Daniel, who earned $195,000 for the victory. 'I haven't won since 1995. I think a lot of people thought I'd never win again. I always believed I could.'
Daniel bested the mark of 46 years, five months and 11 days set by JoAnne Carner when she won the 1985 Safeco Classic. Daniel's last win was the 1995 Ping Welch's Championship, but her win on Sunday was No. 33 in her illustrious career.
Inkster, who shared the overnight lead with Daniel, shot a 3-under 69 to finish second.
Kim Saiki missed a short putt on the 18th to shoot a 70 and share third place with Grace Park, who carded a final-round, 5-under 67. The duo finished 72 holes at 9-under-par 279.
Daniel and Inkster were tied at 12-under par when they stepped to the par-5 18th tee. Daniel laid up, but Inkster had a chance to reach the green in two as her drive left her 220 yards from the hole in the primary cut.
Saiki and Se Ri Pak in the group ahead of the leaders took a long time to complete the final hole and, in the interim, rain started falling pretty heavily, which caused Inkster to alter her plan. She laid up in the fairway and the two had wedges into the green.
Inkster went first from 108 yards and landed the ball a foot from the hole, but it spun back to 15 feet. Daniel's approach stopped eight feet from the hole.
Inkster's putt came up a foot short and Daniel's fell into the bottom of the cup to deny Inkster a second win of the season.
'You get a putt like that and you've got a chance to win, you go for it,' said Daniel. 'I said, 'I've got a chance, let's roll this thing in the hole.''
Inkster spoke about her decision to lay up when she had 215 yards to the front of the green at 18.
'The more I stood over it, it was raining harder, it was getting wetter and wetter and I saw Beth had laid up and I had been starting to hit my irons good coming in so I decided to play the safe shot and go from there,' she said.
Daniel held a two-shot lead over Inkster at the 10th hole, but Inkster holed a 20-foot birdie putt to get within one. Daniel only had four feet to match her with birdie, but her putt burned the edge and it was only a one-stroke advantage.
Daniel drove in the rough at 12 and hit her approach into the gallery on the right. Inkster, from the fairway, knocked her shot two feet from the flag and Daniel struggled to pitch her third to the fringe. Daniel's par putt came up three feet short and she tapped in before Inkster rolled home her putt to complete a two-shot swing and take a one-shot lead.
Both players scrambled to make some difficult pars on the back nine, but both were in good shape at the short, par-3 17th. Inkster left her tee shot 15 feet short of the hole and Daniel played hers to three feet. Inkster's putt stayed on the right edge and Daniel's found the bottom of the cup to tie for the lead.
'I hit a lot of good shots out there,' said Inkster. 'I hit a great putt on 17 and on 18 it was just slow and wet up that hill and I hit it right on line, it's just hard to get it going.'
'Juli's a great friend. I have a lot of respect for her as a player,' said Daniel. 'I think it helped having her out there with me today.'
Pak shot a 69 on Sunday to finish in fifth place at 7-under-par 281, followed by Jeong Jang, who carded a final-round 68 to come in sixth at minus-6.
Becky Morgan and Donna Andrews shared seventh at 5-under-par 283, while Janice Moodie and Leta Lindley tied for ninth at minus-4.