William Bates (77) and Henry Thompson (45) showed good form for the hosts but Scarborough's attack, well managed by captain Piet Rinke, kept the scoring rate under control, writes Simon Dobson.
Ben Elvidge bagged a brace as the home side finished on 205-8.
Despite losing an early wicket Brown and Breidyn Schaper (37) put 70 on the for second wicket. Brown continued in aggressive manner and with Elvidge playing a fine supporting role, the pair eased the side home to a eight-wicket win with 12 overs remaining, forging and unbroken stand of 106.
Elvidge made 39no, but Brown was the star, making and unbeaten 103, from 117 balls with 17 glorious boundaries.
Result: Scarborough 206-2 (Duncan Brown 103no, Ben Elvidge 39no, Breidyn Schaper 37) beat *Harrogate 205-8 (William Bates 77, Henry Thompson 45, Ben Elvidge 2-67) by 8 wkts.
In YPLN Division One East, Scarborough 2nds entertained Goole Town at a sun-drenched North Marine Road but suffered their third defeat of the season.
Goole posted 193 all out, with B Shelton too scoring with 53.
Left-armer seamer Hayden Williamson was the hosts' stand-out bowler, taking 4-33, supported well by Prince Bedi and Joshua Branch.
Brad Millburn made 32 and Nick Zakrzewski 23 but no other batter shone as the visitors bowling duo of D England (4-33) and B Lamb (3-38) turned the screw as Scarborough were dismissed for 176.
Result: Goole 193 all out ( B Shelton 53, N Foster 39, W O'Donnell 27, Hayden Williamson 4-33) beat *Scarborough 2nds 176 all out (Brad Millburn 33, Nick Zakrzewski 23, D England 4-33, B Lamb 3-38) by 17 runs.