'James can go all the way to the very top,' said an admiring Steve Davis, who had been beaten 9-4 in Doncaster to finish runner-up for the second year running.
'He put me to sleep in the first session and after that it was always going to be hard to come back from 6-2 down,' he added.
Wattana's victory brought him his third major title of the year, following victories in the Strachan Open and the Humo Belgian Masters. The pounds 70,000 cheque he received for the victory is his biggest of his career.
Wattana, 22 next month, returns home to Thailand today assured of a tumultuous reception from his snooker-mad compatriots, who are likely to make him Thailand's sports personality of the year. A limousine will be waiting at the airport to take him through the crowded streets of Bangkok.
Tom Moran, Wattana's Yorkshire-born manager, echoed the sentiments of the 35-year-old former world champion: 'I don't think we've seen the best of James. Hopefully, this will be the springboard to greater things.'
Davis, ranked No 4 in the world, has not won a title since his victory in the Asian Open last January. 'It's disappointing to have played well in the last couple of months without any reward. But you don't get titles given to you on a silver platter these days,' he said.
COALITE WORLD MATCHPLAY (Doncaster) Final: J Wattana (Thai) bt S Davis (Eng) 9-4. Frame scores (Wattana first): 84-42 80-32 0-86 71-38 78-28 74-44 108-0 45-76 0-96 48-63 78-44 96-8 97-0.