The Japan midfielder joined this summer from Lazio.
Glasner said: "I think he has adapted. I saw a good game from him at Nottingham. He won many duels, he had two finishes, maybe he was not that lucky.
"I know him quite well, so he puts himself also under pressure because he wants to score goals, he had situations, and he's working very hard for the team, and so I think he has adapted."
He added: "We want to play in the Premier League, we want to challenge with all these teams, and what this season told us until now is that we are competitive.
"Yes, we don't get the results. Yes, we are missing some details, some percentages. But I didn't find any game, although we just have three points, where we said there was no chance to win it, so this gives us confidence."