SAN DIEGO — The calendar flipped and so did a switch in the Chargers’ locker room.

“I imagine that’s probably everywhere a little bit,” quarterback Philip Rivers said.

The Chargers greet December against the visiting New England Patriots on Sunday night. It’s a marquee matchup in a marquee month, as far as the Chargers are concerned.

Rivers is 30-6 in December and the Chargers (8-4) are in the thick of the AFC playoff race. The fact that their opponent is the conference’s top team in the Patriots (9-3) just adds juice.

“They all count as one game, win or lose, but I think it’s natural that it all turns up a little bit just from a feel standpoint, the excitement,” Rivers said. “You get down to the home stretch and it just has a little different feel to it. And you throw in the fact that we will play one of the best teams ever, as far as tradition-wise, what this franchise has done over the last 15 years or so.”

These squads have had some memorable contests and Sunday figures to be another one.

The Patriots, fresh off a seven-game winning streak being snapped by the Green Bay Packers, will try to avoid consecutive losses for the first time this season.

The Chargers, just one game off the AFC West pace behind the Denver Broncos, seek their fourth straight win.

Is this the same team that was shut out last month by Miami, 37-0?

“I think it goes to show that any team can get beat pretty bad in this league and any team can go win, go on a streak and win a game,” Rivers said. “It’s funny. I referenced New England weeks ago. When that happened to us against Miami, I referenced it happening to them when they played Kansas City, and all of a sudden they were done. They were done, and since then they haven’t lost since Green Bay. And then I’m watching on tape, and the record says they are the best team in the AFC.

“So, it can happen each and every week. We strung together five in a row, we lost three in a row, we’ve won three in a row and here we are sitting kind of at the top of a pack of wild card teams and playing against arguably the best team in the conference.”

SERIES HISTORY: The Patriots lead 20-14-2 and have won the past two games and five of the last eight. The Pats’ biggest win came when they defeated the Chargers in the 2007 AFC Championship Game, with former Chargers great Junior Seau stuffing a late running play run to seal the victory. The Chargers’ lone title came in 1963 when they defeated the Boston Patriots in the AFL championship game. In the past three games against the Patriots, Rivers has completed nearly 70 percent of his passes, with six touchdowns and three interceptions.