Robert Heyes, a winter recruit from Hallam, was the star of the show as he ran than through the visitors’ hapless batting line-up to finish with sensational figures of 6-7.
George Cowan also claimed 4-19 as Town’s new ball pair dismissed their neighbours in 14.3 overs.
Five Tickhill batsmen were removed without scoring, none of them reached double figures and their total included ten extras.
Doncaster needed seven overs to complete an easy nine wicket triumph which guaranteed they will finish top of the Eastern group.
The reigning ECB Yorkshire South Premier League champions will meet the winners of the Western group – either Whitley Hall or Sheffield Collegiate – in the final at Wakefield Thornes on Saturday, September 19.
The league was organised into a zoned League Cup competition, based on Royal London Cup rules with 40 overs per side, as a result of the coronavirus pandemic which delayed the start of the season until mid-July.
Meanwhile, Sprotbrough continued their impressive campaign in the South Yorkshire League Championship with a six wicket win over Houghton Main.
Richard Belk took 3-13 as Main slipped to 98 all out.
Daniel Wright struck 46 not out to guide second-placed Sprotbrough to a fifth win from seven games.
Askern Welfare sit second in Division One of the Pontefract & District League following a 26-run over Hooton Pagnell.