The 27-year-old striker recently joined the Rams from Blackburn Rovers on a year-long loan deal.
Despite Best failing to score in his opening two games for the club, McClaren is confident that the forward will prove to be a valuable member of the squad during the 2014-15 campaign.
"We want Derby to be his second home where he feels comfortable and starts fulfilling his potential again," he told the Derby Telegraph. "He is capable of doing that. He is only 27 and we believe in him."
Derby are back in action on Saturday when they make the trip to Sheffield Wednesday in the Championship.