Uni, who currently sit top of Group D on goal difference, have had the better of their Round 4 opponents in recent times having completed the double during the 2017 season.
However, the squad will be hoping to improve on last week's performance that saw them claim a hard-fought point against Dianella in stoppage-time thanks to Alex Kretowicz's last strike.
"Whilst it wasn't our finest display of the pre-season in terms of possession and control of the game, it was impressive to see the hunger and character of the boys on Friday night," Josh Marocchi said.
"No one gave up or put their head down, they stuck to the task and we ended up coming away with a valuable point," he added.
Coach Janssen was also impressed with the character of his squad but was quick to switch focus onto the next task at hand.
"It will be another interesting game this Sunday. Ashfield had some close results not go their way in the Night Series so far, but we always know they are up for a tough game."
Ashfield currently sit fourth in the group on three points after succumbing to losses to Dianella and Kingsway but they are fresh from claiming a comprehensive 3-0 win over Swan last weekend.
The match-up will see Janssen continue to experiment with the line-up.
"We will again rotate some players in and out to see another formation in action and to test players in the competition."
With a semi-finals place well and truly on the cards, the skipper urged his players to keep composed, but also seize the opportunities before them.
"I think pre-season is always a wait and see proposition. You never know what to expect from each side and it can be difficult to gauge an overall performance."
"Who doesn't want to play in a finals atmosphere? It's up to the boys now whether or not they want to deliver."
In team news, Sam Carrello and Mark Trevisiol will miss the clash with hamstring injuries, while Lloyd Prout remains sidelined with a knee problem. Midfield trio Conor Devlin, Andrex Xydas and Luke Randazzo return for this week's clash.