After going into the halftime down 10-0, KC battled back in the second half, only to eventually lose to their division rivals by the score of 20-17.
The final dagger that sunk the Chiefs occurred when Matt Cassel was intercepted by Chargers' safety Eric Weddle with under a minute to play in regulation.
Here are five things that we learned about the Chiefs from Sunday's loss to San Diego.
When the Chiefs lost star RB Jamaal Charles to an ACL injury last week, it was unclear who would carry the load this week against San Diego.
After watching their game against the Chargers, it's clear that second-year RB Dexter McCluster needs to be the primary back for the rest of this season, barring injury.
The 5'8", 170-lb McCluster is extremely fast and shifty out of the backfield, as he used his speed to help himself gain yards from scrimmage, including 45 rushing yards on Sunday.
DMC is not likely to ever be a starter for this team in the future, but he is the most explosive running back that KC has until Charles comes back next season.
In 2010, Chiefs' starting QB Matt Cassel threw for 27 TDs and seven INTs while making his first Pro Bowl team.
Many speculated that much of his success was due to KC's vaunted running game that was ranked No. 1 in the league.
After nearly two games without starting RB Jamaal Charles, Cassel has lost both contests and thrown four interceptions during that time frame.
Despite his solid season last year, interceptions like he threw in KC's final drive against the Chargers on Sunday are why many believe that his time is running out as the team's starting quarterback.
Another game for the Chiefs and yet another missed field goal by kicker Ryan Succop.
For the third consecutive game, the former seventh-round pick of the Chiefs has now missed a field goal attempt.
It's starting to look more and more like Succop will not be the kicker for KC's long-term future.
If he doesn't start stepping it up, he could be looking for a new gig in 2012.
After the first two weeks of the season, the Chiefs' defense was easily the worst unit in the entire league.
Giving up 40-plus points in each of the first two games didn't exactly give much hope to a fanbase and city that thought they had a young and emerging defense in front of them.
Even though KC's defensive unit gave up 20 points against the Philip Rivers-led Chargers on Sunday, they still were able to sack him twice and forced the Pro Bowl QB into two interceptions as well.
It might have been a great performance by the D, but it was reassuring to see that the defense has improved since the first two games of the season.
Before Sunday's game, Chiefs' third-year head coach Todd Haley was already on the hot seat after two embarrassing blowouts that his team suffered in the previous two games.
Now, Haley's seat appears to be much hotter after another painful loss to the Chargers.
At least KC made this one more competitive and showed signs of life, but a loss is a loss.
Haley's job security will continue to diminish if his team keeps piling up the losses this season, regardless of how competitive his squad appears.