BALTIMORE -- The Baltimore Ravens' fourth-quarter collapse was not just a nasty blow to the team's playoff chances. The last-minute 34-33 loss to the San Diego Chargers served as a reality check for the final four games of the season.
There is no margin of error left for the Ravens. Not with this defense. Not with this secondary.
The Ravens entered the fourth quarter with a 10-point lead, which historically has ended in victory. But the sellout crowd was on the edge of their purple seats Sunday because this defense is a shell of its once dominant self.
This secondary is arguably the worst in the NFL and the worst in franchise history. It failed to stop quarterback Philip Rivers when it counted, whether it was on third down, in the red zone or in the fourth quarter.
The Ravens were 10-2 under coach John Harbaugh when leading by double digits entering the fourth quarter. Not good enough Sunday.
The Ravens were 30-2 under Harbaugh when scoring at least 30 points in a game. Again, not good enough.
The Ravens were simply not good enough on defense against the Chargers in a game filled with playoff ramifications. Giving up that one-yard touchdown pass to Eddie Royal with 38 seconds left is the type of play that can haunt the Ravens at the end of the season.
"There's going to be points scored, especially when you play against a quarterback like that," Harbaugh said. "Those quarterbacks in this league are going to be tough to defend. We have the players to win. We have good enough players to win, and we have to go do it."
That's a tough sell after watching the premier quarterbacks make the Ravens look like a junior varsity secondary. Rivers, Ben Roethlisberger and Drew Brees have combined for 1,143 yards (average of 381 yards) and 12 touchdowns this month against the Ravens.
Jimmy Smith, the team's top corner, went down with a season-ending foot injury on Oct. 26. Lardarius Webb has been among the NFL's worst cornerbacks, according to Pro Football Focus. And Anthony Levine, a converted safety, has been pressed into starting at cornerback.
The Ravens couldn't stop Rivers on third down. The Chargers converted on their first eight chances and finished 9 of 11 (81.8 percent), the worst conversion rate against the Ravens in their franchise history.
And the Ravens couldn't slow down Rivers in the fourth quarter. It was apparent the bulls-eye was on the Ravens' secondary in the fourth quarter because the Chargers didn't run the ball once in the game's final 13 minutes.
Moving the ball at will, Rivers completed 13 of 17 passes for 151 yards and two touchdowns in the fourth quarter. His passer rating was 142.0.
"Defensively, we knew it was going to be on us, and we just didn't make enough plays on those final two drives," defensive end Chris Canty said. "That ultimately ended up deciding the outcome."
Harbaugh complained about the last-minute pass interference penalty on Levine, which set up the winning touchdown. But linebacker Terrell Suggs and guard Marshal Yanda both said the Ravens can't leave their fate in the hands of the refs.
This loss -- the Ravens' first home one in November since 2009 -- went beyond one play. The Ravens committed a season-high 14 penalties, including three from sack leader Elvis Dumervil lining up offside. "Inexcusable," he said.
Webb got beat so bad on a 12-yard touchdown to Keenan Allen in the first quarter that he wasn't in the shot when it was replayed on a 24 by 100 video screen. Danny Gorrer was beaten on a 59-yard pass in the third quarter and on a 23-yard touchdown throw in the fourth quarter.
"We've got to stop some of the mistakes that we're making because it's getting old," Gorrer said. "The same mistakes shouldn't be happening. We've put ourselves in this situation, so now we've got to fight our way out of it."
It certainly looks like a fight for the Ravens to get into the playoffs. The Ravens (7-5) acknowledged there is no room for error in their final four games: at Miami, home against Jacksonville, at Houston and home against Cleveland.
"If we win them all, we're 11-5," Suggs said. "Usually, that's good enough. It all starts with next week. We definitely need to have that game."