Ward posted a three-day total of 21-under-par 195 to break the LPGA Tour records for winning score in a 54-hole tournament. The previous mark for lowest total was 197 by Sorenstam at the 1998 ShopRite Classic, while the old record for best score in relation to par was 19-under, shared by Pat Bradley (1991 Rail Golf Classic) and Sorenstam (2000 Firstar Classic).
Click here to see Wendy Ward's scorecards from each round.
Ward earned the first prize of $150,000 for the win, her first since the 1998 Hawaiian Ladies Open.
'As far as in my career, you know, it's not that I ever doubted that I couldn't win again, but when you have a dry spell there, you think, 'Are you pressing too hard? Are you not pressing enough?' You start questioning yourself on a lot of things,' said 28-year-old from Texas.
'Finally I just had to tell myself, 'When you get into contention, make the most of it, make the most of every opportunity.' That seemed to do the trick for me this week. It just happened to be my turn.'
Four shots ahead after shooting a course-record 62 at New Albany Country Club on Saturday, Ward got off to a bumpy start in the final round and saw her lead trimmed to just one shot after three holes.
Ward missed a seven-foot birdie putt at the first hole before suffering her only bogey of the tournament when she couldn't save par out of a greenside bunker at the par-3 2nd. Her playing partner Dunn, meanwhile, rolled in an 18-foot birdie at the first and knocked a sand wedge to a foot for another birdie at the third.
Ward battled back to go three ahead with a two-shot swing at the par-5 6th. Although her caddie suggested laying up after her drive found the rough, Ward decided to hit a 5-wood from 205 yards out to get home in two. Her ball settled on the back of the green 45 feet from the hole, and she two-putted for her a birdie that took her to 17-under.
Dunn's tee shot at the sixth landed in the water and she wound up missing an eight-footer for par.
Sorenstam joined the mix with three straight birdies starting at the fifth to cut Ward's lead to two. Dunn tied Sorenstam at 15-under with a birdie at the seventh, but Ward regained her three-shot cushion with an 8-iron to six feet for birdie at No. 9.
Sorenstam and Dunn continued to apply the birdie pressure, Sorenstam with a three-foot putt at the 11th hole and Dunn with a six-footer at the 10th. Ward responded with another accurate iron, this time a 7-iron into a breeze to set up a six-foot birdie at the 11th.
While Sorenstam dropped four off the pace with a three-putt bogey at the 13th, Dunn birdied that hole to move within two at 17-under.
Sorenstam's 9-iron approach at No. 14 left her with a tap-in birdie, but she was running out of holes. She tacked on birdies at Nos. 16 and 17 for a final-round 66 to finish at 18-under 198.
Ward sank a 15-foot birdie putt at 15. She made it two in a row and climbed to 21-under after blasting out of a bunker to a couple of inches at the par-5 16th.
Dunn holed a 20-foot birdie at No. 17 for a 5-under 67. She matched her career-best finish by tying Sorenstam for second.
Rosie Jones, a two-time winner this season, finished alone in fourth at 15-under after a 66. Meg Mallon shot 67 for fifth place at minus-14
Karrie Webb, the top-ranked woman golfer in the world, tied for sixth with Kelli Kuehne and Amy Fruhwirth at 13-under 203.
Defending champion Lorie Kane tied for 12th place at minus-11.
Full-field scores from the Wendy's Championship for Children