Tim Sheens' side held their nerve this afternoon to deliver the result needed to claim third place in the Qualifiers and the final automatic top-flight spot.
Knowing they had to beat already-relegated Widnes Vikings by at least 14 points, the Robins eventually achieved that with relative ease, veteran playmaker Danny McGuire, in particular, using his vast experience to guide them home.
All of which means, the Million Pound Game will now be contested between Toronto Wolfpack - who dropped to fourth - against London Broncos in Canada on Sunday evening to decide the last vacancy in Super League.
Rovers shrugged off the absence of influential captain Shaun Lunt - hospitalised on Wednesday with a serious infection - and then the eighth minute loss of Australian stand-off Todd Carney to take early control.
The 34-year-old Maurice Blair - normally used at second-row - showed all his versatility by coming in and effortlessly taking over from Carney, proving once more that he has been one of the club’s most valuable signings of recent times.
With him and McGuire pulling the strings, the East Yorkshire club were already 20-0 up by half-time, former Leeds Rhinos captain McGuire having created all three of their tries.
First, his short pass sent James Greenwood over in the eighth minute and then it was his perfectly-weighted chip that saw Ben Crooks collect to ease any early nerves in the home ranks.
There was some tense moments thereafter, not least when Chris Atkin tried a shirt drop-out that ended up gifting Widnes a set on their own line.
But, overall, the hosts looked comfortable enough and they underlined their superiority when McGuire created their third.
He raced onto Mase Masoe’s offload from inside his own half and found Atkin on his shoulder who scored for the sixth successive match, although the final pass did look forward.
Craig Hall improved all three tries and had also added a penalty to leave Rovers in command.
Then it was just a case of making sure they did not ease off.
They did not. Although points did not come with ease, Sheens’ side were rarely troubled and, with a sterling defensive effort, kept Widnes pegged back for the crucial opening period of the second half.
Rhys Hanbury tried breaking clear with a chip ahead but the Widnes full-back - playing his last game before heading home to Australia - blew the chance when re-gathering and sending his pass forward.
Matt Whitley was also called back for a far less obvious forward pass from Harrison Hansen.
Crucially, from that possession, Rovers scored the try that essentially sealed it all.
Junior Vaivai got in at the corner following a quality handling movement in the 57th minute.
Hall hit an upright with his conversion attempt but, after he bundled Owen Buckley into touch with another fulsome tackle, the tall winger slotted a penalty to stretch the lead further.
It was Hall - such an important recruit from Leigh Centurions just before the Qualifiers - who then scored to take his tally to 14 tries in just eight games.
Up front, props Robbie Mulhern and Nick Scruton put in terrific efforts as did loose forward Chris Clarkson who was really industrious in the middle while Greenwood and Joel Tomkins continually tore into Widnes in both defence and attack.
As frustrations boiled over, Widnes' Tim Gilmore was sin-binned late on for dissent. And then the party began for Rovers.
Hull KR: Atkin; Hall, Crooks, Vaivai, Oakes; Carney, McGuire; Maose, Lee, Scruton, Greenwood, Tomkins, Clarkson. Substitutes: Mulhern, Blair, Kavanagh, Tickle.
Widnes Vikings: Hanbury; Marsh, Brand, Runciman, Buckley; Lyons, Gilmore; Houston, White, Hansen, Whitley, Dean, Leuluai. Substitutes; Heremaia, Wilde, J Chapelhow, T Chapelhow.
Referee: Chris Kendall (Huddersfield)