Nial Quinn has revealed the ‘phenomenal power’ Roy Keane brought to Sunderland during his time as manager. The former Manchester United midfielder was brought in as manager by Quinn after the Black Cats made a terrible start to the 2006-07 Championship season. With the Wearsiders languishing near the bottom of the table, Quinn turned to his former Republic of Ireland team-mate – and the impact was instant. Under Keane, Sunderland went on a barnstorming run, winning the Championship title to return to the Premier League. But while Keane’s impact on the pitch was clear for all to see, Quinn has also revealed how the Irishman helped to reignite the passion behind the scenes too. “When he first came to Sunderland, we were still trying to sell 27 executive boxes,” Quinn said in an interview with The Times. “We organised a function for North East business people. Roy walked into the room and it fell silent. He worked that room and didn’t hold back. “We sold out in an hour and a half. He got in his car, went home. I could tell 100 stories like that. “The guy has a phenomenal power.” Keane, 47, managed Sunderland until resigning in February 2009, citing difference was then Black Cats shareholder Ellis Short .