No two NFL teams hate each other more than the Pittsburgh Steelers and Baltimore Ravens.
But from that intense rivalry there grew an admiration and eventually a partnership between a defensive coach named Mike Smith and an offensive coach named Mike Mularkey.
"Mike was in Pittsburgh and I was in Baltimore, and when you had to prepare for a Mike Mularkey offense, you spent a lot of time doing so," Smith said. "I spent a lot of sleepless nights in breaking down his tapes."
Smith coached the Ravens' defensive line from 1999-2001, including the 2000 team that won the Super Bowl. Mularkey was the Steelers' offensive coordinator from 2001-03.
"What gave you headaches were all the shifts and different motions, and all the personnel groups you had to chart," Smith said. "You were worrying about all that different fancy stuff he was doing, but underneath it all, at the end of the day, Mike's core philosophy was he wanted to hit you right in the mouth. I didn't like that then, but I like that now."
Smith had been Jacksonville's defensive coordinator the past five seasons when he was hired as Falcons head coach before this season. He had never been a head coach before, so the task of assembling a staff was new.
But he knew immediately who he wanted as his offensive coordinator: Mike Mularkey.
The two had never met, nor worked together. It was a relationship born from those sleepless nights.