Because of his good performances at Oțelul, Deac was preserved in the CFR Cluj roster for the 2008–09 season. In the first part of the season he made nine appearances. The lack of playing time lead him to consider leaving the club. But with the upcoming new coach Dušan Uhrin, Jr., Deac gave up this plan, receiving assurances that he would be used more. In the 2009–10 season, the team managed to win the league title for the second time in its history, the coach being Andrea Mandorlini who said "Deac has grown into an incredible manner, quantitatively and qualitatively". In the 2010 Super Cup match Deac helped the team prevent a defeat, pushing the game into the penalty shootout. After the match, he was chosen as Man of the match.