League Two leaders Rovers could open up a nine point gap from second placed Plymouth with a victory at the Keepmoat and at least maintain their 17 point advantage in the automatic promotion places.
And Ferguson believes that opportunity is all his players need to get them up for the mouthwatering encounter.
“In terms of motivation it’s an easy one on Sunday because it’s clear as day – you win and you go nine points clear of second,” Ferguson said.
“There is no other motivation needed.
“You stay a minimum of 17 points ahead of fourth with seven games to go.
“It’s staring you in the face at that point. It’s an easy motivation.
“We need to beat what is in front of us. That is Plymouth on Sunday.
“We need to beat Plymouth if we can, go nine points ahead of second and then it’s up to us to get the points we need to finish the job.”
Rovers could secure promotion as early as next weekend if they win their next two and results elsewhere go their way.
Though they may be within touching distance of a return to League One, Ferguson insists nothing is won just yet.
He said: “The title is not sewn up and neither is promotion.
“People may have said that it’s over but it’s not. It’s not over until it’s over.
“You would say you have one hell of a chance of being promoted right now but we need to just take care of ourselves.”
Ferguson has confirmed goalkeeper Ian Lawlor is fit for Sunday’s game despite suffering a groin injury against Leyton Orient last weekend.
Luke McCullough and Aaron Taylor-Sinclair could both make their first appearances in a matchday squad this season following their remarkable respective recoveries from injury.
Joe Wright is also available but Paul Keegan remains a doubt.