Who's a parent to cheer for?
During the 2011 regular season, the Harbaughs became the only brothers to coach against each other in any NFL game (the Ravens beat the 49ers 16-6 on Thanksgiving Day that year).
The NFC West champion 49ers (13-4-1) opened as 5-point favorites, seeking a record-tying sixth Super Bowl title to add to those won by Hall of Fame quarterbacks Joe Montana and Steve Young.
Lewis was the MVP when the AFC North champion Ravens (13-6) beat the New York Giants in 2001.
With Kaepernick's terrific passing — he was 16 of 21 for 233 yards and a touchdown in only his ninth career NFL start — and two TD runs by Frank Gore, San Francisco erased a 17-point deficit to beat the Atlanta Falcons 28-24 Sunday.
Baltimore then fashioned a comeback of its own, scoring the last 21 points to defeat the New England Patriots 28-13, thanks in large part to Flacco's three second-half touchdown tosses, two to Anquan Boldin. Lewis and the rest of Baltimore's defense limited the high-scoring Patriots to one touchdown.
In the often risk-averse NFL, each Harbaugh made a critical change late in the regular season in a bid to boost his team's postseason chances. Clearly, both moves worked.
After 49ers quarterback Alex Smith, the starter in last season's overtime NFC title game loss to the Giants, got a concussion, Jim switched to Kaepernick for Week 11 — and never switched back. Now San Francisco has its first three-game winning streak of the season, at precisely the right time.
Baltimore, meanwhile, was in the midst of a three-game losing streak when John fired offensive coordinator Cam Cameron and promoted quarterbacks coach Jim Caldwell to replace him.
The 50-year-old John is 15 months older than Jim and generally the less demonstrative of the pair, although John certainly did not lack intensity while making his case with officials a couple of times Sunday.