Oxfordshire's Deta Hedman let slip a healthy lead as she lost to Lisa Ashton in the final at Lakeside on Saturday.
It looked as though the top seed, who is based in Essex, was odds-on for her first world title as she raced into a two-set lead and was a leg away from victory as she led 2-1 in the third set.
However, Ashton hit back in devastating style to win the next five legs to level the match at 2-2 and then won the first leg of the deciding set.
World No 1 Hedman briefly rallied to take the second leg of the fifth set, but Ashton hit double six to win the third leg and double ten for the title.
Meanwhile, Stephen Bunting, yesterday won his first world title after beating Alan Norris 7-4 in the men’s final.
The 28-year-old, from St Helens, withstood the challenge from fellow Englishman Alan Norris with both playing in their first final.
After the match was level at 3-3 going into the interval, Bunting then stretched into a 6-3 advantage.
However, Norris clawed the deficit back to 6-4 with a 140 checkout, but top seed Bunting held his nerve in the 11th set.