Arnold's comments come as the two teams prepare to square off in round one of the A-League at Allianz Stadium on Saturday night.
The City Football Group's financial commitment to making Melbourne City an A-League powerhouse continues to grow and includes the establishment of a $15 million training facility, which was unveiled in February, as well as strengthening the club's playing roster.
It is now 21 months since the takeover of Melbourne City by the group was announced and Arnold said the first-round fixture was a massive game for both clubs.
"Well, when you look at what Melbourne City have got, they're the richest club in the country, they've got the best training facilities in the country and they've got one of the biggest clubs in the world helping them with their recruitment and helping fund them," Arnold said.
"So it's something any club would like to have. It's a great opportunity for them to show what they've got and for us it's a difficult game this weekend, but we're very confident in the ability we've got and we're at home.
"We're going to put in a good performance for our supporters who haven't seen us play for quite a while."
Asked if the huge financial commitment to City by the club's owners put added pressure on the team to do very well, Arnold said "well, I think it puts them more in the spotlight."
"As Melbourne Heart they weren't in the spotlight and their expectations were lower and it will depend on how their players handle the pressure from above, and by that I mean the demands of the owners from Manchester City and the club.
"They've got some experienced players and they've got some young players as well and it's going to be interesting to see how they handle that."
Melbourne City finished fifth last season, after the higher-placed Perth Glory was relegated to seventh as part of that club's penalty for cheating the salary cap.
City then beat Wellington Phoenix in the first week of the finals before losing to Melbourne Victory, in a grand final qualifier, who then went on to beat Sydney FC in the decider.
Melbourne City star Erik Paartalu said the aim was improve this season.
"We're certainly looking to make a bigger mark in the league this season," Paartalu said.
"We finished fifth last season and that's not good enough for a club that is as ambitious as ours."
Among the attractions for Sydney FC in round one will be the debut of the club's overseas marquee signing, Filip Holosko, whose pedigree includes a long stint at successful Turkish club Besiktas, as well as 65 caps for the Slovakian national team.
"Filip had one club in seven years, so it shows you what a good and solid person he is, and it was a top club in Besiktas, which shows what a top quality player he is as well," Arnold said.
"So we're expecting big things from him."
"People shouldn't look at him as a replacement for Marc Janko at Sydney FC, because that's not the case.
"He's a totally different style of player. He's powerful, he's quick, he's strong and he's at the perfect age, 31, to come here and do great things.
"He's adjusting a little bit to the hard grounds that we're having at the moment, but he's been very good."
Holosko said he was loving life in Sydney and was keen to make a big impression on the right wing.
"Graham is a great person and a great coach, maybe the best coach in the country," Holosko said.
"It is very good working with him. He was the coach of the Australia national team before and is very good quality.
"Last year Sydney made the grand final and I hope this year we can win it.
"I hope I score some goals and make some assists and I help my team to win the grand final. To me, the team is the most important thing.
"I hope it's a good season. We need to start well against Melbourne City and hopefully go all the way from there. I'm very excited about this game."
