Sports Illustrated has put out a piece on the “Biggest gut-punch loss” for each and every franchise, the Chargers included.
The game that the author the piece, Doug Farrar, picked is an interesting one – a game that stopped the Chargers from getting to the AFC Title game vs the Colts during the 2007 season.
San Diego Chargers: Jan. 14, 2007, AFC divisional round—Patriots 24, Chargers 21
This is the third gut-punch loss for Marty Schottenheimer. This was the best team he ever had—the 2006 Chargers won 14 games, their two losses were by a total of six points, and RB LaDainian Tomlinson set the NFL record for rushing touchdowns in a season with 28. The Chargers sent nine players to the Pro Bowl, and their progress through the playoffs seemed to be a fait accompli. San Diego put up a 14–3 late in the first half of this game, but the Patriots, as has been their wont through the Belichick era, found ways to win. In this case, it was the simple matter of standing out of the way and letting the Chargers shoot themselves in their collective foot, over and over. Schottenheimer’s team turned the ball over just 15 times in the regular season, but did so four times against the Pats. The real killer came when Tom Brady threw an interception to Chargers defensive back Marlon McCree, who tried to run the ball instead of going down. He fumbled, and the Patriots recovered.
Schottenheimer was roundly criticized for several play calls in the game, and between that and his longtime feud with general manager A.J. Smith, he became the only head coach in NFL history to go 14–2 and lose his job.