Central Coast beat Adelaide 1-0 at Bluetongue Stadium on Saturday night but need to beat Wellington on the road in the final round to make certain of top spot going into the finals after Brisbane held on to beat Newcastle, also on Saturday night.

The Mariners were lucky not be down by at least a goal at half-time and showed enormous character to dominate the bulk of the second half.

"I thought in the first half we lacked the killer instinct in the final third," Arnold said. "You never win anything by passing on responsibility. The second half was much better, the boys did exceptionally well."

Arnold was especially pleased with the contribution of young goalkeeper Mathew Ryan, who hit back strongly after his blunder allowed Perth to score the only goal against the Mariners last week.

It is shaping as another massive week for the Mariners with a midweek Asian Champions League clash followed by one of the most important games in the club's history against Wellington.

Win that match and the Mariners will claim the Premier's Plate.

“We’ve got a great record in Wellington, a fantastic record against them and a very good record over there since I’ve been here so we’ll go there very very confident to get what we need,” he said.

“At the start of the year our goal was to get in the top six. To replicate what they’ve done last year already and get second spot guaranteed, it’s been a phenomenal performance by the players.”

He added: “The will to win within this group is great."

Adelaide coach John Kosmina was pleased with the effort of his players, especially in the second half with Mariners pressing so hard for a second goal.

"There was a lot of times during the game when the Mariners couldn't break us down," he said.

"We could have had a couple of goals in the first half and in the second half we came back into it quite well after they scored."