Some have questioned Emery's management of the Japan international.
But he insists: "Kubo has a process. On the one hand, the road to Villarreal and on the other hand, the road to Kubo. And we all want Villarreal to benefit from Kubo's development and Kubo to benefit from Villarreal at the same time.
"He made his debut with us in Europe and still shows commitment and involvement in the team. On a daily basis, I am very happy with him and his work."