Radrizzani eventually appointed Marcelo Bielsa, who has gone undefeated in three Championship games. But the Italian believes promotion to the Premier League would've been guaranteed had Conte, who left Chelsea in the summer, taken the helm.
"I do not deny that I made an attempt for Conte, I have a weakness for him, I would have offered £20m too," he told La Gazzetta dello Sport.
"With him, I was sure that promotion to the Premier League would have been assured.
"There was an interview with Ranieri, an exquisite person. He was flattered by our interest, but at that moment he declined waiting for the right call.
"I also contacted Martinez, but there were not many margins because of his agreement with the Belgian national team.
"But we are extremely satisfied with Bielsa, we have chosen one of the best in the world."