A disappointing season opener didn't shake coach Mike Singletary's confidence in the San Francisco 49ers' defense.
"When I look at our defense," Singletary said this week, "our defense will be a great defense this year."
The 49ers will get an indication where that unit really stands on Monday night when San Francisco hosts defending Super Bowl champion New Orleans.
The Saints had the league's top-ranked offense last season on the way to the franchise's first NFL title.
New Orleans will test the 49ers with a passing attack led by defending NFL passing champion Drew Brees that ranked No. 2 in the league last year.
It's a barometer game for the San Francisco defense, which had its hands full last week with a Seattle passing game that ranked 25th in the league in 2009.
The Seahawks routed the favored 49ers 31-6, and quarterback Matt Hasselbeck left that game as the NFC's leading passer after riddling the San Francisco secondary for 18 completions in 23 throws and two touchdown passes.
The 49ers' improvement this week will have to start there in a game they need to win to prevent their first 0-2 start since 2004.
With all 11 starters returning from last season, San Francisco anticipated big things from its defense after a successful 4-0 preseason during which that unit ranked among the league's best in several categories.
The 49ers got off to an auspicious start at Seattle when cornerback Nate Clements intercepted Hasselbeck on the game's first play from scrimmage. San Francisco's defense dominated the action early, limiting the Seahawks to 11 net yards and no first downs on their first three possessions.
But Clements and cornerback Tarell Brown both gambled attempting to jump routes in the second quarter, with both plays leading to Seattle touchdowns that put the Seahawks in control.
Defensive coordinator Greg Manusky, whose unit allowed only 242 total yards last week, said he doesn't plan to alter his approach much against the high-powered Saints.
"What we've got to do as a defense is, I always want players to make plays," Manusky said. "I want players to be aggressive, go after balls and pick balls off in the secondary and amongst the linebackers. They're a talented offense, so it's just what it is. Let's go get some sacks, play great run defense, get after the quarterback."
San Francisco's rushing defense, which ranked No. 6 in the NFL last season, was typically stout against the Seahawks. But the 49ers fell short in other areas, getting to Hasselbeck for just one sack.
Starting outside linebackers Manny Lawson and Parys Haralson, the key pass rushers in San Francisco's 3-4 defensive scheme, recorded no sacks or quarterback pressures.
That position will get a boost Monday by the return of Ahmad Brooks, who has not played since he sustained a lacerated kidney during practice Aug. 6. Brooks had five sacks in San Francisco's final five games last year as the 49ers led the NFL with 27 sacks over the last half of the season.
The 49ers also will be looking for improvement near their own goal line. San Francisco's defense ranked third in the NFC in red zone efficiency last season, but Seattle scored each of the four times it got inside the San Francisco 20-yard line last week, including three touchdowns.
"The one thing that was disappointing to us in Seattle is that we felt we played very, very well defensively, but the one area that we had some slippage was the red zone," cornerback Shawntae Spencer said. "That's an area we really pride ourselves on. We just really have to get back to it if we're going to be successful."
They'll also have to contain Brees, who is 4-0 against San Francisco as a starter, passing for 1,221 yards and 10 touchdowns with only two interceptions in those four games.
The 49ers are well aware of the challenge they face against Brees and his many weapons, particularly Manusky, who worked with Brees previously when both were with the San Diego Chargers.
"I love Breesy, he's a talented quarterback," Manusky said. "He gets rid of the ball and understands where the ball's going. You've got to sit back and pick your poison, go after him and keep him thinking all the time."