Tony Dungy learned a critical lesson during his Hall of Fame coaching career. When facing your mentor - or someone you guided yourself - take pride, enjoy the atmosphere.
Then forget all about it.
This weekend, Bill Belichick will work against his former offensive assistant, Bill O'Brien, when the Patriots host the Texans in the divisional round. Dan Quinn, once Pete Carroll's assistant, will lead his Falcons against Carroll's Seahawks.
Last Sunday, it was Giants coach Ben McAdoo against his former boss in Green Bay, Mike McCarthy.
''If you are not careful, you can go against tendency,'' says Dungy, who coached a bunch of times against one of his mentors, Denny Green.