Washington spent $57 million in the off-season to shore up the middle of its defense, signing Dana Stubblefield and Dan Wilkinson.
The New York Giants, however, got more from their defense on Sunday.
Stubblefield and Wilkinson helped hold New York to 82 rushing yards, but their effort was overshadowed by that of their counterparts.
"Our defense played lights out," said Giant cornerback Conrad Hamilton, whose interception and return started the big third quarter. "It was just like we played last year. For this team to win, we do have to play lights out each week."
New York defenders had eight sacks and intercepted successive passes from Gus Frerotte early in the second half to set up two quick touchdowns for a 24-10 lead.
Strahan had five tackles, two sacks and the interception return for his first touchdown since his youth football days.
"This is like hitting that 61st home run for Mark McGwire," said Strahan, no stranger to hyperbole. "It's just like you're on top of the world."
The interceptions were only part of Frerotte's problem. He sprained his left shoulder trying to make a tackle on the Hamilton return and re-injured it when sacked minutes later.
Third-string quarterback Trent Green, who got to play because backup Jeff Hostetler has a knee injury, took over for Frerotte after the second hit. He completed 17 of 25 passes for 208 yards and two touchdowns to twice get Washington within seven points.
Green had Washington on the New York 38 in the final minutes before the Giants held.
"This is just like it was last year," Giant safety Tito Wooten said. "Nobody gives us any credit for anything. We had one of the top-ranked defenses last year, and we are going to have one of the top-ranked defenses this year."
Danny Kanell completed 15 of 28 passes for 159 yards and two touchdowns for New York.
Hamilton, filling in for injured Jason Sehorn at right cornerback, started the Giants' big third quarter, grabbing the rebound of a pass tipped by fellow corner Phillippi Sparks and returning it to the two. Fullback Charles Way scored on the next play.
Less than a minute later, Strahan intercepted a Frerotte pass.
A 62-yard pass from Green to Michael Westbrook set up a four-yard scoring pass to Larry Bowie, cutting the Giant lead to 24-17.
But New York answered just before the quarter ended on a 22-yard scoring pass from Kanell to Amani Toomer. It came one play after Keith Hamilton recovered Green's fumble.
Washington closed to 31-24 in the fourth quarter on one-yard touchdown pass from Green to Stephen Alexander.
"We're going to be a good football team," Redskin Coach Norv Turner said. "You can't do the things we did today and be a good football team on the road."