The South Korean spent last campaign on loan at Sunderland, and he believes that his spell at the Stadium of Light means that he is better prepared to hit top form ahead of the new Premier League season.
Asked if he thought he had improved since arriving in Wales, Ki told the club's official website: "Yes, I think so. It feels like a new start for myself and everything has gone well so far.
"It was tough at Sunderland at first because we had a new manager and the team wasn't right. But as time went by we developed and we survived.
"I have grown up a lot and I have a lot more confidence and experience. This is my third season in the Premier League, and I want to grow as a player and improve to help the team."
Ki moved to the club from Celtic in 2012.