The Centurions made a perfect start with two tries in the first eight minutes from second rower Craig Briscoe and winger Jonny Pownall, plus a conversion from Martyn Ridyard. Prop Dominic Maloney pulled a try back and Liam Finn kicked the first of eight goals but Pownall stretched his side's lead to 14-6 with a length-of-the-field opportunist try.
Rovers captain Stuart Dickens brought his side right back into it when he swooped on a loose ball and Finn nudged the home side in front for the first time with the second of four penalty goals. Maloney came into his own, charging over for his second try and breaking clear to get full-back Ian Hardman over for Rovers' fourth try.
The visitors finished the game with 12 men when forward Kevin Henderson was sent off three minutes from the end for a high tackle on Featherstone loose forward Kyle Briggs.
The Centurions will have the chance to set up a re-match with Rovers in the final at Warrington on September 30 when they host Halifax or Sheffield in next week's final eliminator.