The lasting image from the Bears' trip to San Francisco was 49ers defensive end Aldon Smith running amok.

And now Chicago's battered offensive line gets to face Jared Allen, Chad Greenway and the Vikings on Sunday at Soldier Field.

No, Minnesota (6-4) is not in San Francisco's class for creating mayhem with a physically imposing defense. But the way the Bears (7-3) are blocking - make that NOT blocking - for their quarterbacks, just about any team will be a major challenge, whether it's Jay Cutler back from a concussion, or backup Jason Campbell on the field.

"You're going to play a great team on their home field, a place that we've struggled at," Greenway said. "But this is a new year, a new team. And I think we're going to have a focus going in there that we're going to give ourselves a chance.

"It's going to take our best effort. It's going to take our best game of the year to win out there this week."

To get that win, the Vikings figure to emphasize their ace, Adrian Peterson, and the running game, while fitting in throws to Percy Harvin, who also is having a strong season. They must be careful not to fall victim to Chicago's ball-hawking defense, which did little against the 49ers, but otherwise has been brilliant. The Bears have seven interception returns for TDs and have forced 30 turnovers, the most in the league.

The Vikings don't get many takeaways, but they can get after quarterbacks. Allen has 13 sacks in eight games against the Bears, including 3 1/2 in last year's season finale.

Whichever defense sets the tone figures to swing things in its team's direction.

Green Bay (7-3) at New York Giants (6-4)

The last time they met, New York eliminated a 16-1 Packers team from the playoffs. At Lambeau Field.

The Giants will need to rekindle the overwhelming pass rush that was decisive in that game, plus get Eli Manning back on track. He's struggled the last two weeks, both losses, and hasn't played particularly well in a month. A better running game also would help him.

Green Bay, though, has five straight victories and is tied with Chicago atop the NFC North. In his past seven games, Aaron Rodgers has 24 touchdowns, four interceptions and a 117 QB rating. There's a chance he could get back top receiver Greg Jennings from a torn abdominal muscle, too.

San Francisco (7-2-1) at New Orleans (5-5)

As intriguing as any game on the schedule for many reasons.

The 49ers could get back quarterback Alex Smith from a concussion, but with the way Colin Kaepernick performed in a rout of the Bears on Monday night, it's uncertain who will get the call from coach Jim Harbaugh.

Regardless, it's the San Francisco defense that could decide things. If the 49ers can put pressure on Drew Brees and the increasingly dynamic Saints offense - Aldon Smith leads the NFL with 15 sacks - they could control matters. But New Orleans has won three straight and five of six, and Brees could become the third player with 30 TD passes in five seasons.

Atlanta (9-1) at Tampa Bay (6-4)

Atlanta lost for the first time two weeks ago, then needed to rally to beat Arizona. The Falcons have won six of the past seven meetings with the Bucs, but those were different Tampa teams. This one is as potent on offense as, well, Atlanta.

Buccaneers rookie Doug Martin already has rushed for 1,000 yards and seven touchdowns.

"Their rookie running back has had some really explosive games," Smith said. "It will be a challenge for us."

But covering Roddy White, Julio Jones and Tony Gonzalez will be a huge challenge for the Bucs.

Baltimore (8-2) at San Diego (4-6)

The Ravens will have star safety Ed Reed as they seek their fourth successive victory and eighth in nine games. His one-game suspension for illegal hits was overturned on appeal and instead he was fined $50,000.

Reed and the Baltimore defense haven't played close to the level of previous standards, but did have a strong performance in taking charge of the AFC North last week at Pittsburgh.

San Diego, loser of five of its last six, leads the NFL in throwing interceptions (14) as Philip Rivers struggles without much supporting talent compared to previous years.