Striker Matt Simon admits the whole Central Coast side were "off their game" in their 6-2 thrashing at the hands of Western United last weekend.
The Mariners suffered their 14th loss of the season against United. They remain rooted to the bottom of the A-League table with just four wins from 19 matches.
"It’s been tough after that result," Simon admitted.
"As a whole we were off. With the 6-2 results sometimes you have games where two or three players are off, but as a collective we were off our game.
"We’re working hard to rectify that and the boys are feeling good coming into Sunday. It’s a huge game for us at home."
Gianni Stensness scored his first A-League goal in the four-goal defeat to Western United.
"The goal he scored on the weekend was a cracker but the result probably overshadowed that," Simon said.
"But I’m sure in the future he’ll be able to lool back and remember his first goal as an A-League player."
Central Coast host the in-form Wellington Phoenix at home this weekend.
The Phoenix are sitting in fourth spot on the ladder and eyeing a finals birth and Simon is expecting a difficult encounter.
"They’re doing really well, they’re up the top of the table and playing good football," the centre forward said.
"They’re well-organised, well-structured and our staff will come up with a game-plan that will get us the three points and it’s up to the payers to execute it."