EAST RUTHERFORD, N.J. — Trent Dilfer became the latest quarterback to suffer the wrath of Osi Umenyiora, Michael Strahan and the New York Giants' defense.

Umenyiora scored on a 75-yard fumble return and the defense helped to account for 24 points as the Giants won their fifth straight with a 33-15 victory over the San Francisco 49ers on Sunday.

The dynamic four-end defense of the Giants (5-2) had a field day against the NFL's worst offense. New York forced four turnovers by the 49ers (2-4), sacked Dilfer six times and made him play with his head on a swivel while Alex Smith rested his ailing shoulder on the sidelines.

Michael Strahan had his biggest sack performance since 2003, collecting 2 1/2 against his former defensive coordinator and current 49ers coach Mike Nolan.

Eli Manning threw touchdown passes to Amani Toomer and Jeremy Shockey, and Brandon Jacobs ran for 107 yards and a touchdown for the Giants, who also got two field goals from the struggling Lawrence Tynes.

Dilfer threw a 17-yard touchdown pass to Arnaz Battle to give the 49ers a 7-6 lead early in the second quarter before the Giants' defense took over. He added a 1-yard touchdown pass to Darrell Jackson in the waning seconds. San Francisco also got a safety on a blocked punt.

After giving up 80 points in its first two games, the Giants' defense has surrendered 53 in its last five, not counting 17 points on special teams and offensive mistakes.

Besides his fumble return for a touchdown, Umenyiora set up the Giants' go-ahead touchdown in the second quarter, recovering a Frank Gore fumble at the 49ers 27.

Four plays later, Jacobs powered around the right side and scored from 5 yards for a 13-7 lead.

Dilfer, who couldn't get together with Gore on the handoff that led to the fumble, made another mistake on the next play from scrimmage when he didn't see Sam Madison on a short pass. The Giants cornerback jumped the route and intercepted the pass, setting up Tynes' 29-yard field goal for a 16-7 edge.

Tynes, who missed the extra point on the Giants' game-opening drive that Manning capped with a 4-yard pass to Toomer, added a 39-yard field goal just before the half.

Manning, who was a so-so 18-of-31 for 146 yards in a game the Giants dominated, completed passes of 24 yards to Toomer and 18 to Plaxico Burress on the two-minute drill.

Umenyiora broke it open on the opening possession of the third quarter.

With the 49ers at the Giants 15 with a first down, the defensive end came around the right side, sacked Dilfer and knocked the ball out of his hands. He quickly got up, grabbed the ball and ran down the field with nothing but Giants surrounding him. At about the 5-yard line, he tiptoed into the end zone, backing in to put an exclamation point on his touchdown that put New York ahead 26-7.

Middle linebacker Antonio Pierce, called for two foolish roughing the passer penalties against Dilfer, atoned in the fourth quarter, picking off a pass deep in 49ers territory and returning it to the 5.

Manning found Shockey for a meaningless score a couple of plays later.

The only thing that went wrong for the Giants was that Burress' six-game touchdown streak came to an end.

Dilfer finished 23-of-38 for 209 yards in his second start since Smith was hurt late in September. Gore finished with 88 yards on 14 carries, but the 49ers' offense didn't improve much coming off a bye week.