Lewington played under the Italian for the 2008-09 season.
"He's the best manager that I've had at MK Dons, his all-round skill set," said Lewington, the MK Dons captain. "We've had some very good managers here, Di Matteo and people like that. Karl's quite far ahead of where he was at the same time.
"For such a young manger Karl's very focused and doesn't stray away from his principles. He sticks to his guns. If we don't score we'll keep passing it, whereas some people change their mentality."