And while there's no bad blood between the two parties, Ono leaves the Wanderers with a heavy heart and harbours hopes of coming back.
Western Sydney confirmed on Thursday the Japanese playmaker will leave the club when his contract expires at the end of this season to join J-League division-two side Consadole Sapporo.
Ono was approached by Sapporo in November and said he held out making his decision in the hope the Wanderers would offer him an extension.
"I got this offer in November and I had to think about what I want to do," he said on Friday.
"It was very tough to make a decision to go back.
"I wanted to stay as long as possible with the Wanderers because I love to stay, I love to work with this team.
"It's very tough but I decide to go."
Asked if things would have been different if the Wanderers had also made him an offer, Ono said: "Yes of course.
"Yes, I expect offer from the Wanderers because I think they maybe wanted to offer to me but I decide before that. I hope."
The Wanderers cited homesickness and a desire to be back with his family as the main factor in Ono's return to Japan.
Ono dismissed that as the reason and also dismissed any suggestions he was lured by a big money deal or by a lengthy contract.
"It was a great offer because of their vision and what they want to do," he said.
"It's not important money, it's not important how long.
"My family is not the reason I go back home.
"But these are difficult questions. I can't say much because the season is still going.
"I can say everything after the season."
Ono says his aim is to help Sapporo in their charge to win promotion to Japan's top tier but before then his only focus is making sure the Wanderers win back-to-back premierships and go one better with a grand final triumph.
Ono, who has played at big-name clubs in the Netherlands, Germany and Japan, added that he thought the Wanderers were by far the most professional side he had been involved with and he'd encourage other Japanese players to make the move Down Under.
"I want to be a kind of bridge between Japan and Australia," he said.
"I want to keep contact with the Wanderers forever and if there are good players in Japan of course I want to bring them here.
"But I'm not an agent," he said with a laugh.
The former Japanese international has no intention of Sapporo being his final club and hopes to overtake Kazuyoshi Miura, who is still playing in Japan's second tier at the age of 46.
Asked if he would ever consider one day coming back to the A-League as a coach Ono said: "I want to come back to here as a player."