The 22-year-old from Barbados took the first World Cup hat-trick by a West Indian with bowling figures of 6 wickets for 27 runs.
Chris Gayle (80) and Kieron Pollard (60 from 27 balls) took the Windies to an imposing 330-8 on a pitch of irregular bounce, before Roach got stuck in.
The fast bowler produced some exhilarating pace as the Netherlands capitulated for 115 runs.
Roach’s hat-trick, with the first three balls of the 32nd over (his ninth), saw Pieter Sielaar and Bernard Loots beaten for pace and trapped lbw, before last man Berend Westdijk had his middle stump flattened in emphatic style.
The West Indies’ total was the highest at the Feroz Shah Kotla stadium, which had only recently returned to international service following a 12-month suspension over a dangerous playing surface.
Even when South Africa had beaten West Indies at the same ground last Thursday, however, there were signs that batting remained a tough proposition.
And although West Indies, surprisingly inserted by Dutch skipper Peter Borren, encountered few alarms, a few deliveries barely bounced as they skidded through the dry surface.
Gayle’s innings was a sensible one. The former skipper dropped anchor in a 100-run stand for the first wicket with Devon Smith (53), while Pollard provided the theatrics late on, hammering five fours and four sixes in the third-fastest World Cup half-century. Ramnaresh Sarwan chipped in with a 42-ball 49.
By contrast, the Dutch batsmen floundered in the face of early strikes from Roach and left-arm spinner Sulieman Benn (3-28).
Roach went on to collect only the sixth World Cup hat-trick and the first of the tournament, as well as the eighth-best figures recorded in the ICC’s flagship event.
(The content used in this article was lifted from BBC Sports)