A strong pass rush had Lions quarterback Matthew Stafford under duress all night and earned the Bears’ defense an A+. (US Presswire)

The Chicago Bears offense has been up and down, but the defense has been spectacularly consistent since the first week of the season. 

It was again Monday night in the 13-7 victory over the Detroit Lions when the offense came out strong for a change but then stalled after Jay Cutler's rib injury. Nevertheless, the defense played at a high level throughout and made up not only for the offensive inconsistency but for a rare off-night by special teams.

Offense: B-

Slow starts plaguing the Bears offense were replaced by a slow finish. Cutler's injury had something to do with it, but the spotty pass blocking and offensive line penalties also contributed. Some credit for making it difficult has to go to a Detroit Lions defensive front. Chicago's running game was effective early, but struggled with only 62 second-half yards when teams typically run better and kill clock. When it was effective, much of it came from quarterback scrambles. That's no way to keep your quarterback healthy, and they didn't. WR Brandon Marshall continues to beg the question, what did they ever do without him? Previous grade: B+

Defense: A+

Getting a good pass rush early on Matthew Stafford made him uneasy in the pocket and had a lot to do with his errant passes. CB Charles Tillman was physical with WR Calvin Johnson, the usual approach he takes, and it worked. Johnson had only three receptions and 34 yards. The defense continued forcing turnovers at an impressive rate with four more and added a new wrinkle -- three red-zone takeaways. Nothing frustrates an offense more. The Bears lead the NFL with 21 takeaways. Previous grade: A+

Special teams: C

When Robbie Gould gets a field-goal attempt blocked and Devin Hester averages only 5.0 on punt returns, it's not a typical Bears special-teams day. The unit offset this problem with a timely muffed punt recovery by newly signed and former Bear Zack Bowman. The coverage units made up for some of the return game's failures, holding Stefan Logan to 1.2-yards per return on six punts and 22.0 on kick returns. Previous grade: B

Coaching: B+

Twice the Bears called timeouts in the first half -- once on offense and once on defense -- in what appeared to be a waste. But they came out of both timeouts with strong stands. Mike Tice stuck with the running game even when it was inconsistent, and he easily could have panicked and gone to the pass. He had Cutler moving his launch point, which helps against a strong pass rush. He probably could have done it more. Rod Marinelli's defensive scheme had the Lions confused early with back-to-back defensive back blitzes. It's something the Bears never do. They did have trouble adjusting to the Lions' use of an unbalanced line with an extra tackle. Previous grade: A

Follow Bears reporter Gene Chamberlain on Twitter @CBSBears.