Against the Vikings, it was the Chargers' stout run defense -- it entered ranked No. 7 -- which took it on the chin as Adrian Peterson shredded it for an NFL-record 296 rushing yards and three touchdowns. The Vikings' 378 rushing yards set a Vikings franchise mark.
Now a pass defense that has been inconsistent this season must tangle with Manning and his stable of top-notch receivers.
"It's always a challenge against him," linebacker Stephen Cooper said. "It's like playing chess out there against him. He's trying to see whatever coverages we are in and we are going to have to disguise them as much as possible."
Sunday's game marks the second time this season the Chargers have faced an AFC heavyweight. In Week 2, the visiting Chargers got hammered by the Patriots, 38-14.
"They took it to us," right tackle Shane Olivea said of the Patriots' domination. "And I would definitely say you try to learn from every game. We can't play the way we did against New England against Indianapolis.
"But it was early in the season."
"I know as coaches and players we were trying to work together and get used to each other," Cooper said.
But the Chargers (4-4) took a major step backward in Minnesota when snapping their three-game winning streak. And their schedule only grows tougher, with dates against Jacksonville, Baltimore, Kansas City and Tennessee.
But first the Colts arrive.
"They are an elite team and we have to come back and play our best," Olivea said. "We want to be an elite team, too. And to do that you have to be good year in and year out. We don't want to be a one-year wonder."
After going 14-2 last season, the Chargers were eager to show that season wasn't a fluke. But as the season matures, it's obvious the Chargers aren't building on their best regular season in franchise history.
What's working in the Chargers' favor is residing in the AFC West. The watered-down division could allow the Chargers to sneak into the playoffs as a first-place team. That looks to be their best chance halfway through a disappointing season.
They remain tied for first with the Chiefs, although the Chiefs have the tiebreaker over the Chargers thanks to their victory last month in San Diego.
The Chargers, though, have shown resiliency in the recent past and they will need it after Sunday's stunning defeat to the Vikings, who entered the game at 2-5.
Whether the Chargers still possess that comeback magic under new head coach Norv Turner will be determined. The team will find out soon enough when facing the balanced Colts. The players realize there is more to Sunday's opponent than its offensive stars.
"Definitely the offense, because of Peyton Manning, it gets a lot of attention," Olivea said. "But defense is what wins championships."
--CB Antonio Cromartie set an NFL record by returning a failed field-goal 109 yards for a touchdown. It was Cromartie's third touchdown in two games and he has scored them in three different manners. The others were a bad punt snap recovery in the end zone and he returned an interception for a score.
--CB Quentin Jammer aggravated his hamstring injury in the first half and didn't return. That will likely limit his practice time this week.
--WR Craig Davis missed another game with his persistent ankle injury. The Chargers spent a first-round pick on Davis and he has yet to contribute significantly.
--DE Luis Castillo (ankle) was pulled from the game after injuring his right ankle. He underwent surgery on Monday and will be out six weeks.
--C Nick Hardwick (foot) is likely out another week.
--OLB Shaun Phillips (groin) hopes to go this week after sitting out the Minnesota game.
--QB Philip Rivers looks to rebound from one of his worst pro days. Rivers was 19-of-42 for 195 yards, with an interception and a lost fumble in the loss.