The defense put them in position to win and appeared to have all but delivered a win.
Then Melvin Ingram leveled Drew Brees and let the air out of a defining moment.
Ingram may have just got Brees' facemask after the New Orleans Saints quarterback had let sail on an underthrown pass, but he may as well have taken off Brees' head.
The play certainly had the affect of doubling over the Chargers.
Chargers linebacker Demorrio Williams had intercepted the throw Brees made under duress and returned it 26 yards for a touchdown that appeared to give the Chargers a three-score lead with three minutes left in the third quarter.
Instead, the 15-yard roughing the passer penalty gave the Saints first down at their 32.
They scored five plays later, the first of their 17 unanswered points to end the game en route to their first victory of the season.
View the photo gallery: Chargers-Saints 10/7/2012
View the photo gallery: Chargers Fans 10/7/2012
A game the defense was poised to remember as confirmation of their ascension is now, at best, a chance to learn.
“You can’t give him that many chances,” cornerback Quentin Jammer said of Brees. “You have to put your foot on their throat. That’s something we didn’t do. We did, but …”
Ingram, the first-round pick who plays with a speed that has helped transform the overall ability of this defense, took the blame steadfastly.
“It was just me playing hard,” Ingram said. “I take full responsibility … It’s a tough lesson to learn, but it has to be learned.”
The rookie did say he will “go that way again” but repeated he will learn to pull up short (or maybe hit a little lower) when chasing quarterbacks.
And perhaps the Chargers will eventually be able to recover from in-game adversity.
Just as Ryan Mathews’ fumble in their only previous loss this season left the Chargers’ jaws agape, they hardly seemed in the game again after the penalty.
“We couldn’t find a way to get the momentum back,” linebacker Shaun Phillips correctly observed.
The Chargers maybe tuckered themselves out escorting Williams to the end zone and then celebrating.
The Saints marched down the field essentially unfettered.
Brees hit Marques Colston for a 16-yard touchdown pass that pulled the Saints to 24-21 with 11 seconds remaining in the third quarter.
A Chargers team that had pressured ably and covered adequately suddenly couldn’t even slow the Saints.
And the offense played as if in a stupor until the game’s final series as well.
After the Chargers punted, the Saints advanced 90 yards in nine plays to take a 28-24 lead.
An interception and return to the Chargers’ 16-yard line set up a field goal that stood as the final margin.
In all, Brees completed 10 of his 12 passes for 159 yards following the Ingram hit.
To that point, while the game seemed destined to be remembered as Meachem’s breakout and Mathews’ comeback, it should have been appreciated for what the defense did against one of the league’s top offenses.
The Saints had the ball with two minutes to play in the first half. They had converted four of their previous five third downs and already scored two touchdowns and were poised to drive for what could have been a two-touchdown lead with the ball coming to them to start the second half.
But on a third-and-six from the 49, Corey Liuget sacked Brees. The Saints punted, and the Chargers got the ball with 1:48 remaining before halftime.
They took four plays to go 86 yards for a 17-14 lead on Meachem’s second touchdown reception of the game (and second as a Charger).
Then, Brees’ first pass of the second half, on third-and-five, was intercepted by Jammer at the New Orleans 34 and returned to the 25. Mathews ran and leaped 13 yards for a touchdown three plays later.
It was exactly what the Chargers said they’d have this season – offense and defense playing simpatico, complimenting each other.
It seemed the defense was putting together the string of games it takes to build an impenetrable confidence.
Defensive takeaways had led to 24 points last week in Kansas City and another seven, then seemingly 14, on Sunday.
A new coordinator, who hiccupped in his first chance to stop an explosive offense two weeks ago, has dialed up the pressure since. Brees was having to move much of the night, throwing uncomfortably at times. The secondary was largely responding.
Then it collapsed.
The last time something similar happened, two weeks ago against Atlanta, the Chargers responded strongly the following Sunday.
They’ll need to again.