They started seven new players on defense in the season opener, but the performance in a 29-19 loss at Minnesota was no better than a typical performance last season when the Saints yielded an average of 28.4 points per game.
The Vikings rushed for 129 yards and Sam Bradford had a career game, completing 27-of-32 passes for 341 yards and three touchdowns.
"We struggled in coverage at times," Saints head coach Sean Payton said. "For the early portion of the game, penalties hurt in the first series. As the game wore on, I thought the explosive plays hurt us. There were some (mental errors), poor decisions. Overall (it was) not good enough."
Now New Orleans has to try and slow down Tom Brady and New England's potent offense Sunday in the Mercedes-Benz Superdome.
"We've got a good offense coming in," safety Kenny Vaccaro said. "We've got to be a lot better than we were last week."
The Patriots lost their opener to Kansas City (42-27), but the offense still had 371 yards, 124 rushing and 247 passing.
The Saints were hurt by poor execution on third down, allowing Minnesota to turn 9-of-14 third downs into first downs and Minnesota twice scored touchdowns on third-down plays.
"Obviously, we have to be better in communicating in our third-down situations," linebacker A.J. Klein said. "We had some completions for first downs that were just communication errors, things that can be fixed between us and the rest of the back seven, but it was obviously a lackluster performance and I think a lot of it was self-inflicted. The score says it all."
The Saints defense committed three unsportsmanlike conduct penalties in the first half, two of which occurred on Minnesota's opening drive, which ended with a field goal.
"We've gotten better as a defense. We showed that in the preseason," Vaccaro said. "I don't know what happened. It was one of those things where we were wrong on all levels of the defense. So was (the opener) a fluke or are we delusional?
"It was embarrassing the way we lost. To take a step back like that really hurts. We've got to get this win."