It seems Canadiens general manager Marc Bergevin isn’t afraid to admit when he has made a mistake. Bergevin failed to reach a long-term agreement with restricted free-agent defenceman P.K Subban before an arbitration hearing Friday morning in Toronto and it appeared the two sides were drifting apart as they left Subban’s immediate future in the hands of arbitrator Elizabeth Neumeier. But there was an opening for renewed negotiations while Neumeier was given 48 hours to make her decision and there was a dramatic turn of events Saturday when the team announced Subban had agreed to an eight-year, $72-million contract that runs through the 2021-22 season. It’s the longest — and richest — deal in Canadiens’ history, eclipsing the six-year, $39-million deal goaltender Carey Price signed in 2012. “We are very pleased to have reached a long-term agreement with P.K. Subban,” Bergevin said in a statement. “This agreement helps consolidate the future of our team. A key element of our group of young veterans, P.K. plays with a high level of intensity every time he steps onto the ice. Despite his young age, he carries a great deal of experience and brings contagious energy to the team. Defencemen of his level are a rare commodity in the NHL.” You can bet that wasn’t what Bergevin was saying in the arbitration hearing Friday. But Subban said it was educational to hear the Canadiens catalogue his faults, and if the experience left any scars on his psyche they weren’t showing during a 30-minute conference call with the media from his home in Toronto on Saturday evening. Subban said he never doubted the two sides would reach an agreement and that the negotiations continued after the arbitration hearing. He said both sides were aiming for a long-term deal and that staying in Montreal was more important than the money. In the end, he got both.