The strong winds that whipped Summerlea Golf & Country Club throughout the week also made their presence felt Sunday. Overnight leader Catriona Matthew, who had put together three straight rounds of 70, struggled to a 5-over 77. She tied for second alongside Michelle Ellis and Michele Redman at 1-under-par 287.
'I played in wind like that in Hawaii,' said Mallon. 'But the combination of factors -- how hard, how firm the course was and how hard the greens were, and then to add that wind on top of that, it was just a nightmare at times.'
Mallon began the day one stroke off the lead and was steady on the front side with a 12-foot birdie at the par-3 sixth. On the back side, Mallon drained a 15-footer for birdie at the 11th to reach 7-under.
Matthew, who picked up her only birdie of the day at the opening hole, was also at 7-under after making the turn. However, the wind derailed her consistent play on the inward nine.
At the par-4 12th, Matthew was forced to take a penalty drop after her tee shot went left into the bushes. She chopped out and then hit a 3-iron right of the green. Matthew's chip left her within five feet, from where she two-putted for triple bogey.
The Scot could not recover and bogeyed the following par-3 13th. Matthew added another bogey at 15 and closed with a three-putt bogey at the last.
'It was very tough,' said Matthew. 'Especially since the wind picked up on our back nine. Even holes down wind were playing very difficult. You were just trying really to make pars. I just had a couple of bad swings that got me into a lot of trouble.'
Mallon also found trouble on the back with three bogeys, but was still able to hold off her competitors for her first win in two years.
'It was really a great test of patience,' said Mallon, who collected $180,000 for the victory and vaulted from 13th into sixth place in the 2002 U.S. Solheim Cup points standings. 'I think the front side was the key, because I got under par and then was able to get some cushion going into the backside.'
The 39-year-old's last victory came at the 2000 du Maurier Classic, the now-defunct LPGA major that was played in Canada.
Se Ri Pak carded a round of 3-over 75 to finish alone in fifth at even-par 288. Charlotta Sorenstam and Gloria Park were next at 1-over-par 289.
Canadian Lorie Kane collected four birdies and three bogeys en route to one of only five under par scores on Sunday. Kane posted a 1-under 71 to finish alongside Laura Diaz and Susan Ginter-Brooker at 2-over-par 290.
Karrie Webb, who won the Women's British Open last week at Turnberry, struggled with a final-round 76 to finish alone in 14th at 4-over 292.
Full-field scores from Canadian Women's Open