EAST RUTHERFORD, N.J. — Five years after being traded away in a draft-day swap for Eli Manning, Philip Rivers came back and stuck it to the New York Giants.

Rivers capped an 80-yard drive with an 18-yard TD pass to Vincent Jackson with 21 seconds to play and San Diego stunned the Giants 21-20, posting their third straight win while handing New York its fourth straight loss.

San Diego (5-3) is now well positioned for the second half of the season. The Giants (5-4) can only shake their heads in disbelief as their first 5-0 start since 1990 is a distant memory.

"It's a big emotional win," said Rivers, who threw for 209 yards and three TDs. "... The link between me and Eli is always going to be there. So yeah, it's a little special.''

Rivers had the Giants to thank for giving him the chance to pull the game out. Giants cornerback Terrell Thomas returned an interception 33 yards to the Chargers' 4 with 3:14 to play. If Manning and company had punched the ball in, the game would have been over. But a first-down holding penalty on Chris Snee pushed New York back 10 yards and it settled for Lawrence Tynes' second field goal, a 22-yarder with 2:07 to play for a 6-point lead.

"We had a chance and you can't leave that team in the game," said Manning, who was 25 of 33 passing for 215 yards and two touchdowns. "You can't leave that team an opening."

Rivers connected on six of eight passes in the winning march.