They visit KCOM Craven Park to face the Championship league leaders winners in their opening Qualifiers game on Sunday.
Halifax stunned Rovers by beating the promotion hopefuls in their last match, the final regular round 28-6 victory at The Shay which dramatically secured Marshall’s side a spot in the Middle Eights.
That was only KR’s third league defeat of the entire season - they also lost at home to Toulouse the week before - but they were without a raft of key players.
Marshall admitted: “We were really pleased with how we performed against a strong Hull KR team last time out.
“We know they will be stronger this time - Shaun Lunt will come back in and Mose Masoe will probably play and whoever else - but we’re confident.
“We’ve got momentum going in and, though it’s never easy playing over in Hull, we did a good job there earlier in the year.
“I think we were only one try adrift going into the last 10 or 15 minutes so we weren’t far off and this doesn’t daunt us.
“It will be a different challenge this weekend as their season relies on beating sides like ourselves in the Qualifiers.
“And they will be confident. They’ve been good in the Championship all year. Obviously the last two games they have fallen away but I do think they had one eye on the Qualifiers then.
“We’ve gone the other way and built into the Qualifiers; we’ve actually got better and that makes it a great tie.
“On paper the two teams are poles apart financially but if you work hard from one to 17 anything is possible and we know that.”
Halifax, who held a half-time lead at Craven Park in March before losing 28-14, won their last four games to surge into the Qualifiers and set-up ties with Super League sides like Warrington Wolves, Catalans Dragons and Widnes Vikings.
But while Rovers - intent on winning an immediate return to Super League - have strengthened their squad with the recruitment of former St Helens Grand Final-winning prop Masoe from St George Illawarra and ex-Castleford Tigers winger Justin Carney, Marshall’s side have no such luxury.
“We know we’ve not got a big squad,” he added.
“Jacob Fairbank played with a broken hand in that last game.
“We felt the risk was worth taking but we’ll probably not use him again this week. The bone’s not quite healed.
“He got through it but we had to pad him up and jab him up to do that.
“Brandon Douglas, the kid we’ve got from Castleford Tigers, will come in.
“He hasn’t played the last two games due to a couple of shoulder issues but the rest will mean he’s ready to ramp it up against a strong KR pack.
“James Saltonstall played in reserve grade on Wednesday night but I don’t think we’ll make too many changes.
“We gave them around a week off after that last regular game but by the time Sunday comes we’ll have had three quality sessions.
“We’re happy with what we’re doing and if they have the same confidence and belief and play well there’s no reason why we can’t get the result.”