Goals from Matt Simon and John Hutchinson did the damage for the Mariners who managed to take second spot on the A-League table, removing Adelaide United who have been there for almost the entire season.
Arnold admitted he did not expect the Mariners to be where they are but said he would take it nonetheless.
"I didn't think at the start of the year we'd be in second place because our goals were to make the top six, and still our goal is to make the top four but we're going to give the top two a real shake," Arnold said after the match.
"Overall I think for the third game in a week, we've had Wellington, Brisbane and now Newcastle here, I'm very proud of the boys' performance. It was a bit sloppy at times but overall you've got to be happy with a 2-nil win over Newcastle."
Central Coast will travel to Perth today for Wednesday's clash with the Glory at nib Stadium and Arnold said there would be no risks taken in regards to players and their fitness.
"We've got a tough trip to Perth tomorrow and we have to play in Perth on Wednesday," he added.
"Looking at the boys today and what I was thinking beforehand, I don't think we can take some of the players that played today because of fatigue, we can't afford to risk an injury because of all the travel. If a player gets a soft tissue injury now they'll probably miss the rest of the season."