Shanahan's play-calling acumen, which has long been admired in NFL circles, was never more apparent than it was three years ago, during the first two-and-a-half quarters of Super Bowl LI. As the Atlanta Falcons' offensive coordinator -- with Matt LaFleur, who completed his largely uplifting rookie season as the Packers' head coach with a 14-4 record, serving as quarterbacks coach -- Shanahan's creative game plan helped produce a 28-3 lead over the New England Patriots, confounding one of the greatest defensive geniuses in the sport's history in the process. But Bill Belichick's Patriots, led by legendary quarterback Tom Brady, spoiled the storyline with an epic comeback, and Shanahan left to take over a Niners team that was in the midst of a major rebuild.