The Cottagers midfielder says the Dutchman has given the players a lift.
"I can only say good things about Rene," Parker told the Daily Mail. "You only have to look at his track record, who he's worked with. He's very positive with lots of good ideas.
"After a couple of sessions you know if a coach knows what he is doing. Rene has that confidence I like. It's something I've seen in the Dutch before. There's a fine line between arrogance and confidence but these guys have it right. The manager is the same and having them here makes you feel safe."