And then, suddenly, it was over.

The Colts, AFC South champions each of the past five seasons, the AFC’s No. 2 seed in the playoffs this season and the Super Bowl champions a year ago, outgained their first opponent in the 2008 NFL postseason on Sunday. They had more first downs. They had the ball longer.

Their quarterback threw for more than 400 yards and three touchdown passes.

The thing the Colts didn’t do Sunday in the final game in the 24-year history of the RCA Dome was what they most needed to do.

They didn’t execute well enough, players and coaches said afterward.

And because of that, they didn’t win.

The Colts (13-4), after 13 regular-season victories, took the lead twice in the first half and twice more in the second, but the AFC West Champion San Diego Chargers (13-5) rallied each time for a 28-24 victory in an AFC Divisional Playoff Game in front of 56,950 at the RCA Dome Sunday.

The Chargers, playing without 2006 NFL Most Valuable Player LaDainian Tomlinson for three quarters and starting quarterback Philip Rivers for the final period, were as resilient Sunday as the Colts had been throughout the season.

San Diego took leads of 14-10 and 21-17 in the third quarter, then took its final lead with 4:50 remaining when backup quarterback Billy Volek scored on a 1-yard sneak.

That made it, 28-24, Chargers. And in this case, the four points were enough.

The Colts had the ball twice in the final five minutes with a chance to take the lead.

First, the Colts drove from their 23 to the Chargers 7, but on 4th-and-goal with 2:06 remaining, Manning threw incomplete to running back Joseph Addai.

The Colts’ defense then forced a San Diego punt, after which Indianapolis took possession at its 32 with 1:30 remaining.

Manning threw five yards to Addai, but Manning threw incomplete on the next play, and on 3rd-and-5, wide receiver Reggie Wayne was injured on an incomplete pass down the middle.

On 4th-and-5 from the 37, Manning’s pass caromed off the fingers of Colts tight end Dallas Clark.

The Chargers, who entered the game with a seven-game winning streak, will play the New England Patriots (17-0) in the AFC Championship Game at Gillette Stadium in Foxboro, Mass., Sunday at 3 p.m.

The Colts lost after a first-round postseason bye for the third time in eight seasons.