LAKE FOREST, Ill. – As they prepare to host the undefeated Tennessee Titans Sunday at Soldier Field, the Bears are counting on their defense to pick up where it left off against the Detroit Lions.

Alex Brown and the Bears defense had reason to celebrate in the second half Sunday against Detroit.

After yielding 23 points in a forgettable second quarter Sunday, Chicago pitched a shutout in the second half in turning a 23-13 halftime deficit into a 27-23 victory.

“The second quarter was not one of the best quarters we’ve played,” said coach Lovie Smith. “They did pretty much what they wanted to do to us, but we liked the way we picked it up in the second half of the football game. We had to stop them and the guys were able to do that.”

The same defense that permitted three touchdowns and a field goal in the second quarter didn’t allow the Lions to score on eight second-half possessions.

Detroit’s two best opportunities were thwarted by takeaways as rookie safety Craig Steltz made a leaping interception one yard deep in the end zone and linebacker Lance Briggs forced and recovered a fumble on a 6-yard reception by tight end Michael Gaines.

“Our guys did a great job,” said defensive coordinator Bob Babich. “They came in at halftime and made a decision that [the Lions] weren’t going to score. We let them drive the ball a couple times into field goal range, but we did whatever it took to keep them out.

“It was a big-time gut check. We have a lot of pride. Things didn’t go well in the first half. We could very easily have tucked in our tails, but the players made a decision that, ‘This is it.’”

The Bears didn’t change their game plan in the second half; they just played with more intensity after seeing a 10-0 first-quarter lead turn into a 23-13 halftime deficit.

“We jumped out to that 10-0 lead and it seemed like we kind of relaxed a little bit,” said defensive tackle Dusty Dvoracek. “I don’t know what happened. We didn’t execute. We didn’t play well in the second quarter, but for three quarters we played real well.”

“We just got back to the basics,” said cornerback Nate Vasher. “I don’t think there were a lot of bells and whistles. We just lined up, played hard and fast and played physical and finished the ballgame. That was huge for us.”

Lance Briggs forced and recovered this key fumble in the fourth quarter of Sunday's win over the Lions.

Although the Bears registered their only two sacks on Detroit’s first two possessions, the defense generated its most consistent pass rush in the second half.

Israel Idonije pressured Dan Orlovsky into an incompletion and batted down another pass, while Brian Urlacher forced the Lions quarterback to heave a third-down throw out of bounds to avoid a sack, drawing an intentional grounding penalty. Tommie Harris and Mark Anderson also pressured Orlovsky into key incompletions.

“It’s critical every week,” Idonije said of the pass rush. “As a defense, you want to get pressure on the quarterback. That makes it difficult for an offense to get into a rhythm. The defense coming in and keeping as much pressure on as we did, it helps and it’s effective.”

While the Bears (5-3) have won four of their last five, the Titans (8-0) will enter Sunday’s game as the NFL’s only undefeated team. The Bears haven’t played an opponent with a better record since Dec. 8, 1929 when the Packers improved to 12-0-1 with a 25-0 win at Wrigley Field.

Sunday’s contest at Soldier Field will feature a strength-versus-strength match-up with a Bears run defense that ranks sixth in the NFL against a Titans rushing attack that ranks third behind rookie Chris Johnson (146 carries for 715 yards and 5 TDs) and LenDale White (98-404-10).

In their last three games, the Bears pass defense has allowed the Falcons’ Matt Ryan (301 yards), the Vikings’ Gus Frerotte (298 yards) and Orlovsky (292) to post season-highs in yards.

While it’s difficult to explain the extreme hot and cold stretches by their veteran defense, the Bears know they must play at the top of their game to hand the Titans their first loss of the season.

“I think if you look at most defenses in the league you’re going to see inconsistent play,” said coach Lovie Smith. “We’ve done a lot of good things defensively.

“What I’m going to choose to remember [from Sunday] is how the defense finished. There was nothing inconsistent about the way we finished that second half. There was consistent good football, and I’m hoping that’s what will carry through the second half of the season.”