Darren Sproles, centre, gets a lift from his Chargers teammates after his first-half touchdown run. (Stephen Dunn/Getty Images)

Darren Sproles scored his second touchdown of the game in overtime to give the San Diego Chargers a 23-17 upset of the visiting Indianapolis Colts in their opening-round AFC playoff game on Saturday night.

Sproles, whose nine-yard run near the end of the first half gave the Chargers their first lead of the see-saw contest, took the ball around the left side and cut in for a 22-yard scamper 6:20 into the extra period.

The diminutive back led all rushers with 105 yards on 24 carries, and added another 45 yards on five catches. He also added 106 kick-return yards and 72 on punt returns.

"You know, when your number is called, you have to be ready," said Sproles, who before his games-winning run fumbled into the end zone, with the Colts recovering.

"Right after that fumble, it was still kind of in my mind," Sproles said. "I wanted that TD back to make up for the fumble."

The Chargers — winners of five straight — move on to meet either top-seeded Tennessee or No. 2 Pittsburgh.

Peyton Manning threw for 310 yards — including a 72-yard strike to Reggie Wayne — but the NFL MVP couldn't keep the Colts (12-5) from having their season ended by the Chargers for the second straight year. Last January, San Diego scored a 28-24 upset in Indy in the divisional round.

"We had chances to put the game away, but we just didn't do it," Manning said after his team lost for the first time since Oct. 27, ending a string of nine wins. "We've been winning those fourth-quarter games. The Chargers just did a better job of executing. Give them credit."

Chargers quarterback Philip Rivers completed 20 of 36 throws for 217 yards with an interception, while LaDainian Tomlinson rushed for a three-yard touchdown in the first half. Tomlinson, who carried the ball just five times, watched Sproles' winning touchdown from the sidelines, where he spent the final 2½ quarters nursing a groin injury.

Penalties play big role in OT

Indianapolis opened the scoring on its second possession with a vintage Manning drive. The veteran passer completed all six of his attempts before Joseph Addai capped the nine-play, 81-yard foray with a one-yard touchdown plunge.

San Diego used a classic combo of its own to tie it early in the second quarter. Tight end Antonio Gates — bad ankle and all — made the key play, shedding tacklers just like old times for a 30-yard catch-and-run that took the ball to the Indianapolis three. Erstwhile touchdown machine Tomlinson, whose best days may also be behind him, punched it in on the next play.

A 43-yard Adam Vinatieri field goal put Indy back ahead, but only until the speedy Sproles found a seam for a nine-yard touchdown 47 seconds before halftime.

Manning helped restore the Colts' lead midway through the third quarter, finding a wide-open Wayne for a 72-yard strike up the left sideline that made it 17-14.

That was still the score when the Colts took over the ball with 2:41 to play and a chance to ice the game. But on third and two from the Indy nine-yard line, San Diego linebacker Tim Dobbins came in untouched off the right edge and planted Manning at the one.

The ensuing punt from the back of the end zone gave the Chargers excellent field position, and Rivers hit Gates for a pair of 11-yard completions that set up an easy 26-yard field goal by Nate Kaeding with 33 seconds left to tie the game.

Manning never even got to touch the ball in overtime. San Diego won the toss, and advanced the ball downfield with the help of two defensive holding calls, the second against Tim Jennings on third-and-8. On the next play, Colts linebacker Clint Session was whistled for grabbing Sproles' facemask.

Sproles scored on the next play, shedding a defender at the five-yard line.

With files from the Associated Press