Should they suffer a loss to Victory the Mariners risk losing top spot - a position they've held for 13 rounds - with the ever-impressive Western Sydney waiting in the wings only a point adrift.
With only six games remaining, the Mariners' schedule is about to get hectic as they juggle the Asian Champions League with their charge to the finals.
But with an ACL match against Korea Republic's Suwon Bluewings in Gosford in Wednesday, Arnold is adamant they won't lose sight of their mission to win back-to-back A-League minor premierships.
"My first priority is to put in a good performance against Melbourne Victory. I want a reaction from last weekend; our performance against Perth wasn't good," he said.
"But it's a footballer's passion to play big games and when you play big opposition there's no motivation needed, it comes from within.
"It's no secret my first priority is the premiership, to get to the last 16 of the ACL, and then the grand final - they're our goals for this season."
Victory too will be looking to redeem itself after going down 2-1 to the Wanderers last week.
But to live up to its name Victory will have to do something no other team has done this season - beat the Mariners on their home turf.
And they'll have to do it without key striker Archie Thompson who will miss the clash due to a persistent hamstring problem.
"We've turned Bluetongue into a real fortress. Our record at home this year is eight wins and one draw from nine games," Arnold said.
Victory has slipped to third on the ladder with the finals looming after two successive losses but coach Ange Postecoglou isn't giving up on taking out the Premiers' Plate.
"Six points, six games, I reckon that's still doable," he said.