Rovers defended superbly to keep the Rams scoreless.
Samoan international centre Misi Taulapapa bagged two tries although he blotted his copybook slightly when he was sin-binned in the first-half.
Rams had earlier had two players sin-binned in separate incidents.
Ex-Rovers player Jason Crookes was the first to be shown a yellow card in the 11th minute for a high tackle and, two minutes later, Taulapapa’s first try put Rovers ahead. Luke Adamson became the second Rams player to be sin-binned in the 23rd minute.
A minute later, Featherstone’s Jamie Foster had an effort ruled out for a double movement.
However, it wasn’t long before Featherstone stretched their lead, John Davies going over and Foster converting. Taulapapa was then sin-binned in the 34th minute. Five minutes after he returned to the field in the second half he grabbed his second touchdown that Foster goaled from the touchline.
Foster kicked a penalty goal and Kyle Briggs landed a drop goal before Rovers sealed victory with Jamie Cording’s 62nd-minute score.
Ian Hardman rounded things off for Rovers with a try six minutes from time, with Foster adding his fifth goal.
Dewsbury Rams: Guzdek, Uaisele, Crookes, Grady, Grant, Sykes, Kain, Groat, Hemingway, L. Adamson, Hale, Trout, Farrell. Substitutes:Conroy, Brown, Muranka, Tonks.
Featherstone Rovers: Craven, Johnson, Hardman, Taulapapa, Foster, Abdull, Thackeray, Bostock, Ellis, Baldwinson, Cording, Davies, Spears. Substitutes: Briggs, Griffin, Roche, Ormondroyd.
Referee: J Roberts (RFL)