October 28, 2008 is the day the San Diego Chargers’ season turned around. That was the day they replaced former defensive coordinator Ted Cottrell with Ron Rivera, the same Ron Rivera that helped make the Chicago Bears NFC Champions in 2006.

Thanks to Rivera’s guidance, the Chargers’ defense went from a unit that was getting beaten on a weekly basis, to a unit that played to their strengths and masked their weaknesses with sound game plans.

In the Bolts’ impressive 23-17 overtime playoff win Saturday night against the Indianapolis Colts, Rivera’s bunch saved their best play for when it mattered most: when the game was hanging in the balance.

After a 72-yard touchdown reception by Reggie Wayne midway through the third quarter to put the Colts ahead 17-14, the Chargers put the clamps down on Peyton Manning and the Indy offense. While Manning did throw for 310 yards and a touchdown, he failed to move his team much in the fourth quarter, including in drives where one more touchdown would have put the game out of reach. The Chargers’ front seven got consistent pressure on Manning, stuffed the Colts’ running game and gave their offense a chance to win. (Which they did.)

And speaking of the San Diego offense, Darren Sproles proved that he is much more than LaDainian Tomlinson’s backup. He rushed for 105 yards on 22 carries and scored two touchdowns, the second of which won the game in OT. While everybody else on the field was going at 100 mph, he seemed to be playing at 150 mph. He truly was the spark that the Chargers needed, and helped take the game of Philip Rivers’ shoulders, which was huge because the NFL leader in passing efficiency wasn’t particularly sharp Saturday night.

What the Chargers did tonight was prove that regular season records mean nothing in the postseason. People can still talk about the Patriots being screwed out of a chance to play for a Super Bowl (which they were), but nobody can say now that the Chargers don’t belong in the postseason. They beat the hottest team in the league, shutdown the league’s Most Valuable Player in the fourth quarter, and displayed a very good young talent in Sproles.

And if Rivera’s defense can continue to play as well as it has over the past month, don’t assume that the Chargers can’t go into Tennessee or Pittsburgh next week and win. They’re playing with house money right now and just picked up some momentum.