Heather Watson said she was proud that years of hard graft has paid off as she became the first British person to win a WTA Tour singles title in 24 years with success in the HP Open in Osaka.
The 20-year-old from Guernsey saved four match points in a long match against Chang Kai-chen of Chinese Taipei to rescue a match she appeared to have thrown away.
She served for the match at 5-3 in the second set, double-faulting on match point, and then seemed about to be defeated in the decider before showing plenty of fight to eventually clinch a 7-5 5-7 7-6 (7/4) win in three hours and 11 minutes.
Watson's victory means she has followed in the footsteps of Sara Gomer, the last British winner of a singles title on the WTA Tour in California in 1988.
The final was an encounter between two unseeded players, who had a total of 33 break points and breaking seven times each.
Watson took the first set by four breaks to three, but dropped her serve three times again in the second to let her 21-year-old opponent back into the match.
Chang served for the match at 5-4 in the final set, but, in spite of four match points, could not see off the Briton, who broke back before holding her nerve in the tie-break.
Watson's win will also move her back above fellow Briton Laura Robson in the world rankings, making her British number one again.
Her victory came a month after Robson reached the final of a WTA event in China, the first time since Jo Durie at Newport in 1990 that had happened.
Watson returned to the court for the doubles final alongside Kimiko Date-Krumm, but they lost 6-1 6-4 to Raquel Kops-Jones and Abigail Spears.