The Robins, relegated in heartbreaking fashion via the Million Pound Game 11 months ago, secured an immediate return to the top flight with two Super 8s games to spare thanks to a tense 12-6 victory over Widnes at KCOM Craven Park.
Victory came in the 700th club match for the 66-year-old Australian, who guided the Kangaroos to victory in the 2013 World Cup before stepping down from the role to resume his career in England.
"I didn't realise it was my 700th game," Sheens said. "Obviously it's a game that I'll remember, that's for sure. In context, it's as good as anything, it's what you're doing at the time.
"I was employed to get the team back into Super League and we've done it today. I suppose it's one job done. We'll enjoy the moment.
"It's a bit surreal really, we've got two games to go. It felt like a Grand Final. The guys are very happy, particularly the ones who were here last year."
Hull KR fell behind to a try from Widnes loose forward Hep Cahill but drew level on the stroke of half-time thanks to a score from centre Thomas Minns and clinched victory with an 80-metre interception try from winger Ryan Shaw 11 minutes from the end.
It preserved Rovers' 100 per cent record in the Qualifiers, although Sheens admits their form has been patchy.
"It's been by the skin of our teeth," he said. "It's not all been pretty but when you get to the semi-finals - and this is what they are - you just need to get across the line. There's been some grit and desperation."
Widnes coach Denis Betts put aside his disappointment to pay tribute to Hull KR's tenacity.
"It's hard to take," Betts said. "It is what it is. We couldn't take our chances when we created them.
"I thought we had the better of the game and did enough to win it but you've got to give credit where it's due. They didn't want to give in.
"That's the best I've seen them play this year. They had tenacity and desire not to lose the game.
"The rules allowed them to slow the game down to their pace. That's the way the game is at the moment, you can take all the tempo out of it. Hull KR did a very good job of managing the situation."
Already without regular full-back Rhys Hanbury, Widnes suffered further injury blows with replacements Corey Thompson and Danny Craven both going off with head injuries, leaving winger Stefan Marsh to fill in for part of the game.
"Losing Danny Craven was a big thing," Betts said. "It killed our attacking structures. Danny's not trained all week and we got a bit disjointed."
The Vikings will now aim to seal the other automatic "promotion" place when they play their final fixtures against London Broncos and Catalans Dragons, who are the next opponents for Hull KR.
"I just hope Hull KR don't party too high this week," Betts added. "I can see it all going down to the wire."