He was nominated for Coach of the Year earlier this week after guiding the West Yorkshire club to third place.
But Grix is hoping they can shrug off a recent dip in form to push on and reach the play-offs semi-finals.
Halifax have lost four of their last five games, including Sunday’s 12-10 home defeat against fellow top-six side Batley Bulldogs.
In contrast, since being promoted from League 1, Whitehaven have impressively won ten of their last 12 games to leapfrog London Broncos into the last play-off spot on the final day.
Along the way, they won 36-22 at play-off rivals Bradford Bulls on Sunday having also beaten Halifax 19-6 in Cumbria the previous week.
But Grix insisted: “We’re pretty confident and there’s no reason why we shouldn’t be.
“Clearly, Whitehaven are the form team in terms of wins and losses but we played them a couple of weeks ago so we know what’s coming.
“No team is going to change much in two weeks at this time of the season. We didn’t really give a good account of ourselves last time and we were disappointed.
“But last week, against Batley, it was a real tough, physical, play-off style game that went down to the end. I don’t think Batley will think I’m doing them any disservice by saying it could have gone either way. If we’d been hammered by Batley I might have got a bit worried going into this.
“But we weren’t. We just couldn’t get over the line when we had a chance and that’s the lesson for us; you don’t get many chances at this time of the season and you have to take them in play-offs.
“To be third past the post in the regular season is something we can be really proud of.
“Hopefully we can push on further now.”
Elder brother Scott Grix, Fax’s 37-year-old full-back, will hope for a win, too, as he announced this week he will retire at the end of the season.