EAST RUTHERFORD, N.J. — Philip Rivers showed the New York Giants exactly what they traded away in 2004, and this one really hurt the team that wanted Eli Manning so much.

Rivers capped an 80-yard drive with an 18-yard pass to Vincent Jackson with 21 seconds to play and the San Diego Chargers stunned the Giants 21-20 on Sunday, handing New York its fourth straight loss.

Rivers was 24 of 36 for 209 yards and three touchdowns, including two to Jackson, in helping San Diego (5-3) win its third straight game. It was the first meeting between the quarterbacks since the trade.

The Giants are 5-4 heading into a bye week and not looking very much like a playoff team.

Rivers also found Jackson on a 10-yard touchdown pass in the second quarter. He hit Kris Wilson on a 2-yarder in the third to give San Diego a 14-7 lead in a game in which the Giants defense rebounded from a miserable efforts the previous three weeks.

But they couldn't put the Chargers away when they had the chance. Terrell Thomas intercepted Rivers' pass late in the fourth quarter and returned it 33 yards to the San Diego 4. A holding penalty on first down pushed New York back 10 yards, and it had to settle for a short field goal and a 6-point lead.

With just over two minutes to play and one timeout, Rivers marched the Chargers down the field. He hit Malcolm Floyd on a 12-yard completion, made two throws to Antonio Gates for 10 yards and had a 21-yarder to Darren Sproles that put the ball at the 18. On the next play, Rivers found Jackson in the right corner of the end zone for the game-winner.

Rivers' touchdown pass to Wilson, which followed a short punt by Jeff Feagles, gave San Diego a 14-7 third-quarter lead before the Giants rallied.

Manning threw touchdown passes of 6 yards to Steve Smith and 8 yards to Kevin Boss, while Lawrence Tynes kicked field goals of 38 and 22 yards.

Manning drove the Giants 60 yards in 10 plays and Tynes got New York within 14-10 with his 38-yard field goal.

The Giants defense, which gave up 112 points in the first three games of the losing streak, then helped them take the lead, recording three straight tackles for losses and forcing the Chargers to punt from their 4.

Domenik Hixon returned the ball to the San Diego 39 and Manning needed only six plays to give New York the lead, hitting Boss on a play when the Chargers were offside.

A bizarre play at the end of the Giants' opening drive cost them 3 points. New York lined up for a 39-yard field goal attempt, but Tynes never got the kick off. Feagles took the snap and Tynes must have seen that Feagles didn't have a good hold, so he didn't kick the ball.

Feagles, who punted badly here two weeks ago, got off a 32-yarder on his first attempt, giving San Diego the ball at the New York 45. Rivers completed passes of 16 yards to Jackson and 19 to Gates before going 10 yards to Jackson for a touchdown on the first play of the second quarter.

The Giants tied the game on the ensuing series on Manning's pass to Smith. It capped a 16-play, 76-yard drive that consumed almost 11 minutes. Manning and Smith kept the drive alive with a 19-yard completion on third-and-18 from the Chargers 44.