The defender is on-loan from Fulham.
Clark said: "He has been absolutely magnificent for us in our three competitive games, I thought he looked very, very mature for his age and he handled everything they threw at him, whether it was the small tricky players or the big lad they put on.
"He has certainly improved, I think he's just getting better and better and I hope he has a similar season for Birmingham as he did for Yeovil last year.
"Then he will go back to Fulham and push for the Premier League squad so at the minute it is benefiting everybody. But I thought all the defence were great today and when they did break through, our keeper was there."
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