Brazilian Rafael Everton Lira has left FC IfeanyiUbah after rejecting a lesser role with the club he led to the 2016 Nigerian FA Cup.
Everton's exit comes four days after he led Anambra Warriors to their first trophy with a win over Nasarawa United.
FC IfeanyiUbah appointed Japanese-American and former Accra Hearts of Oak manager Kenichi Yatsuhashi as its new head coach on Wednesday.
Everton rejected an assistant coach and head coach of youth development role.
Everton, the youngest manager to win the Nigerian FA Cup at 27, said on Facebook: "As of today I am no longer the coach of FC IfeanyiUbah and I would like to thank the club for the opportunity to manage here,"
"The club chairman offered me a position of assistant to the new coach, but I'm going home for vacation to sit down with my agent and family to be able to make the best decision for my career.
"I am grateful for the incredible results as coach of IfeanyiUbah to get the fourth position in the first division and manage to be the Nigerian Cup Champion.
"I would like to thank everyone and thank you for everything."
BBC Sport understands that Brazilian Alberico Barbosa da Silva – one of the stars of the season who helped them to a place in next seasons Confederation Cup – will also be leaving the club.