Littler has experienced a rapid rise in his career since reaching the World Championship final in January at the age of 16.
He moved up to number 31 in the world rankings, securing himself a PDC tour card and a place at every ProTour event this year.
After winning his first PDC senior trophy in Bahrain by beating three-time world champion Michael van Gerwen, Littler faced the Dutchman, 34, in the final of the Dutch Masters, but was beaten 8-6.
The pair met again on night two of the Premier League in Berlin, with Van Gerwen beating Littler in the deciding leg of a thrilling final.
Littler, who collects £15,000 in prize money for the Players Championship success, hit seven 180s and averaged 110 against compatriot Searle, who himself averaged an impressive 111.71 during the final.
Searle, 36, broke back against Littler to take the match to 7-7, before the teenager checked out on double 20 in the deciding leg to seal victory.
Littler said his ambitions now were to qualify for the World Matchplay and World Grand Prix events – two of the sport’s majors.
“That’s what I want to try and do – qualifying for everything, because that’s what I have to do,” said Littler.
“I have to play on the floor tournaments and then hopefully qualify for everything else.”
Littler was not the only player in Wigan on Monday to achieve a nine-darter – when a player scores 501 with the minimum number of darts required – or even the only teenager.
Two fellow competitors managed nine-darters, with 18-year-old Englishman Leighton Bennett doing so against Lukas Wenig and 50-year-old Northern Irish player Mickey Mansell sealing the feat against Krzysztof Ratajski.
