NFL: What matters more than a good QB in these playoffs? A good D

FILE - In this Oct. 29, 2017, file photo, San Francisco 49ers' C.J. Beathard (3) is sacked by Philadelphia Eagles' Brandon Graham (55) and Mychal Kendricks (95) as Malcolm Jenkins (27) looks on during the second half of an NFL football game. One team has a suffocating defense. The other has the NFL's No. 1 unit. Defense should win at least the NFC championship. (AP Photo/Michael Perez, File)

Four of the five teams that gave up the fewest points during the regular season are the last four left with a shot at the Super Bowl, something that had never happened since the NFL-AFL merger nearly a half-century ago.