Harlequins produced a dominant first-half display to shock Hull KR and run out comfortable winners on Friday.
Chad Randall scored the first after a Matt Gafa punt and Louie McCarthy-Scarsbrook charged through for another.
Will Sharp scored a third, but Stanley Gene hit back for the Robins with a try that replays showed was knocked on.
David Howell touched down before Scott Wheeldon replied for Rovers, but tries by Chris Melling, a second for Sharp and a Howell score secured the win.