Both of these teams are strong on first down: the Patriots offense is fifth in DVOA on first down, the Chargers defense eighth. The problem for San Diego comes on third down, where the Patriots rank third and the Chargers 18th. The Patriots were above-average on third down no matter how many yards were left to go, but the main issue here is third-and-short. The Patriots converted 82% of short-yardage situations, leading the NFL, while the Chargers stopped just 22% of these runs, which ranked 31st. Even a stop on third down won’t necessarily stop a drive, since the Patriots converted 16 of 19 opportunities on fourth down.
These issues on third and fourth down are the sole reason why the Patriots’ running game ranks so much higher than the San Diego run defense. If we only consider first and second down, New England’s running game ranks 14th in DVOA and the San Diego run defense ranks 15th. On third and fourth down, New England’s running game ranks second and the San Diego run defense ranks 30th.
The Chargers also need to keep the Patriots out of the red zone, where the Patriots offense is second in DVOA and the Chargers defense ranks dead last. It’s more than just scoring touchdowns instead of field goals. Neither Brady nor the San Diego defense had any interceptions in the red zone.
