FOXBOROUGH, Mass. (AP) — Perfection comes down to one game now.

Despite a shaky Tom Brady, the New England Patriots were still too much for the banged-up San Diego Chargers in the AFC championship game Sunday, pulling out a 21-12 victory that sent them back to the Super Bowl for the fourth time in seven seasons.

Brady made several stunningly poor throws that fluttered in the wind, Randy Moss was a non-factor for the second straight game and the highest-scoring team in NFL history sputtered all afternoon. Instead, the Patriots (18-0) relied on Laurence Maroney’s spins, cuts and helmet-rattling runs.

With injured Chargers star LaDainian Tomlinson reduced to mostly watching in a parka, the Patriots moved on to a Feb. 3 matchup in Glendale, Ariz., against the winner of the NFC title game between the Green Bay Packers and New York Giants.

Yet for all the Patriots have accomplished — they’re the only team in NFL history to start out with 18 straight victories — they’re well aware they must win that final game to avoid being relegated to a footnote.

No matter, New England took care of the nuts and Bolts. The sellout crowd at Gillette Stadium chanted ‘‘Super Bowl! Super Bowl!’’ in the closing minutes, anticipating the Pats’ first appearance in the big game since the 2004 season.

Coach Bill Belichick’s team eclipsed the 17-0 mark of the champion 1972 Miami Dolphins, and will soon try for his fourth NFL title. The Patriots beat the Giants in a 38-35 thriller to close their regular season; New England did not play the Packers.

Tomlinson carried on the first two San Diego plays, and did not touch the ball again because of a bad knee. Chargers quarterback Philip Rivers hung in despite a bum knee and star tight end Antonio Gates did his best with a dislocated toe.

The Chargers (13-6) gave a better performance than early this season, when they were routed 38-14 at New England. They trailed just 14-12 midway in the third quarter this time, but Brady’s 6-yard TD pass to Wes Welker was enough for New England.

Maroney ran for 122 yards to help hold the lead.

The Patriots seemed poised to pull away late in the third quarter, but a terrible throw by Brady cost them. On third-and-goal at the 2, Brady tried a touch pass over the middle that NFL interceptions leader Antonio Cromartie easily picked off standing on the New England logo in the end zone.

Nate Kaeding’s fourth field goal, a 24-yarder midway through the third period, pulled San Diego to 14-12. Too bad for the Chargers, that was the story of their afternoon — they’d drive close, only to wind up settling for a kick.

It was 23 degrees at gametime, making for frosty breaths on the field and putting the Patriots cheerleaders in parkas. Most players chose to ignore the cold and came out in short sleeves.

The brisk wind caused more noticeable problems. The goalposts shook with every gust while passes and punts sailed in crazy directions.

Normally solid in chilly weather, Brady took a while to adjust to the conditions. He badly missed his first two passes — he threw a total of two incompletions in 28 attempts last week in the win over Jacksonville.

A few minutes later, Brady lofted a poor toss that Quentin Jammer intercepted. Belichick talked this week about the Chargers’ ‘‘ball disruption’’ and turnovers certainly were a focus — San Diego led the league in takeaways, the Pats had the fewest giveaways.

San Diego turned Jammer’s pickoff into Kaeding’s 26-yard field goal with 2:55 left in the period.

This wasn’t what the fans at Gillette Stadium expected, and they grew silent at seeing the highest-scoring team in NFL history sputter. The crowd also watched the Chargers refuse to back down, engaging in several post-play scuffles with the heavily favored Patriots. Tomlinson stepped in to calm hard-hitting former teammate Rodney Harrison after some early roughhousing.

The Chargers did a good job at blaketing Moss, determined to deny him the ball. New England eventually got it to him on a reverse, and he snaked loose for a 14-yard run that seemed to energize the Patriots. Moss finished with one catch for 18 yards.

Maroney plunged in from the 1 barely over a minute into the second quarter and, with very light flurries falling, and the Patriots were ahead.

Brady later hit Jabar Gaffney over the middle for a 12-yard TD and a 14-6 lead, prompting several of the Patriots to celebrate. Brady merely walked off the field with his head down.

Kaeding kicked field goals of 23 and 40 yards, and the Chargers trailed 14-9 at halftime. San Diego might’ve gotten more, but Rivers made ill-timed throws that Asante Samuel and Ellis Hobbs intercepted.