Vissel Kobe lost 3-0 to Shonan Bellmare.
Iniesta said, "I'm hurt. No one likes losing. On a personal level, I'm happy to have made my debut but I'm hurt because of the loss.
"I'm grateful for the kind way the fans have responded to me," added Iniesta. "My teammates have been very helpful too. For now we need to keep working hard so the victories start flowing. That's the first step to a happy ending."
"It's too soon to talk about the differences. It's time to for me to adapt. We're talking about talented players, physically strong and the challenge is to improve every time."