The histories of the Los Angeles Chargers and New England Patriots are intertwined with each other.
Both teams began as American Football League teams in 1960, the year the upstart league began its existence.
The San Diego Chargers were the AFL's first powerhouse team, and the 1963 Chargers won the only championship in team history when they beat the Boston Patriots 51-10 in the league's title game.
While the Super Bowl was still years away from coming into existence, that team challenged the 1963 NFL champion Chicago Bears, but the established league did not officially acknowledge the "other league" and ignored the challenge.
The 2019 divisional playoff meeting is just the fourth postseason game between the two teams, and the Patriots won the other two.
The Patriots are once again hosting a divisional playoff game, and they are four-point favorites, per OddsShark, to win that game for the eighth straight year. They have not lost in the divisional playoffs since Rex Ryan and the Jets beat them following the 2010 season.
The game will kick off at 1:05 p.m. ET Sunday at Gillette Stadium, and it will be televised by CBS.
While the Patriots have been an elite team throughout the Bill Belichick-Tom Brady era, they are likely to get a major challenge from the Chargers.
Philip Rivers has had a brilliant year for the Chargers, completing 347 of 508 passes for 4,308 yards with 32 touchdowns and 12 interceptions, and he has as an excellent rapport with wideouts Keenan Allen, Mike Williams and Tyrell Williams.
Tom Brady has not had the explosive passing numbers he has had in the past. He has passed for 4,335 yards with 29 TDs and 11 interceptions, and his big-play tight end Rob Gronkowski has just three TD receptions this year.
Brady will attempt to make key plays with wideouts Julian Edelman and Chris Hogan, along with running back James White.
The temperature for this divisional playoff game is not expected to rise above 30 degrees, and that could make it difficult for either passing game to function at peak efficiency.
The Chargers are going to attempt to run with Melvin Gordon, while the Pats will depend on rookie Sony Michel. The Chargers are averaging 4.7 yards per carry, which ranks seventh in the league, while the Pats gain 4.3 yards per attempt, which is 17th in the league.
White and Gordon played college football together at Wisconsin, and the New England running back knows how dangerous his former teammate is.
"He's always been able to do everything," White said of Gordon, per Nora Princiotti of the Boston Globe. "I think he's gotten better as a pass catcher. He's one of the top yard-after-catch guys in the league, so he's been getting better and better with that each year."
Turnovers are a big key in any postseason game, and the Pats took the ball away 28 times during the season, while the Chargers had 20.
Since the Chargers may be a bit more productive in both the running game and passing games, takeaways may be even more important to the Patriots than usual if they are going to survive and advance to the AFC title game.
In addition to CBS, the game can be viewed on FuboTV
Tickets available through StubHub