With an 11-under-par 277 Fairclough finished one stroke clear of Florence Descampe from Belgium, with Carin Hjalmarsson three strokes further behind after a final round of 66 to equal the course record.
Scotland's Dale Reid, who established the course record on Saturday, was left sharing fourth place with the world No 1, Laura Davies, who had holed putts of 15 and 25 feet for eagles at the long first and 16th holes in her last round of 69.
Not once in the final round did Fairclough exceed par. She had started the day one stroke behind Descampe but drew level when she chipped to four feet for a birdie at the first hole. Fairclough then birdied the fourth and fifth to reach the turn in 33.
She was now three strokes ahead then salvaged a four at the 10th where she drove into a fairway bunker. "That was an important hole," Fairclough said later.
She followed Descampe into the hole from 18 feet for her birdie at the next. When Descampe struck a marvellous recovery from sand to five feet for her third birdie in a row at the 14th Fairclough's lead had been cut to one stroke.
In the two previous rounds Fairclough had struggled over the closing holes when the lead beckoned but she made no mistake this time. She followed a par at the long 16th by striking a superb six-iron safely on to the green at the short 17th hole.
With the large crowds surrounding the last hole, Fairclough again found the heart of the green. Her eight-iron approach pulled up 15 feet from the hole, from where she putted up close to the hole to seal her victory.Reuse content