Often that’s in reference to an offensive turnover, which can put the defense in a bad spot and the momentum on the wrong side. But last Sunday against San Francisco, the context was some difficult field position Capers’ defense found itself in early on.

It was just two possessions, but the state of the game at the time and the results the defense produced showed just how important those situations can be, even in the first and second quarters.

Here’s the recap of the two scenarios:

--Late in the first quarter, the Packers trailed 3-0. San Francisco’s Ted Ginn returned a short punt 12 yards, and a penalty on the Packers added another 5. San Francisco took over on the Green Bay 39-yard line, already threatening to score.

The defense had one lapse, allowing a 25-yard completion to tight end Vernon Davis down to the 2. But the unit held strong from there. Linebacker Clay Matthews stopped running back Anthony Dixon for no gain, defensive end Cullen Jenkins sacked quarterback Troy Smith for an 8-yard loss, and linebacker Frank Zombo chased down Smith on a scramble for a gain of just 2.

The Niners were forced to settle for a field goal, making it 6-0.

--Two possessions later, after the Packers went three-and-out, Ginn returned a punt 19 yards to the Green Bay 48 and the Niners were in enemy territory to start a drive again. But with the help of a false start, the defense got the stop.

Safety Nick Collins and defensive end Ryan Pickett combined to bring down running back Brian Westbrook after a 2-yard gain on first-and-15, cornerback Tramon Williams jumped in front of receiver Josh Morgan on a swing pass and nearly got an interception, and then Jenkins notched his second sack of the game on third down, forcing a punt.

The end result of two possessions that started in Green Bay territory, with the Packers yet to get on the scoreboard, was just three points. The Niners had controlled the field position and for the most part the game for 1½ quarters, yet they led only 6-0.

“To me the sign of a good defense is that you can respond when you’re put out there in poor field position, adversity situations,” Capers said. “I think it started yesterday with our ability to stop the run. We did a good job against the run and got off the field on third down.”

On the two key first-down runs, on goal-to-go from the 2 and the first-and-15 after the false start, the Packers surrendered next to nothing. If San Francisco gets in more favorable down-and-distances there, it could have been a different story.

Imagine the hole the Packers would have needed to climb out of had the 49ers scored a touchdown in the first instance and picked up a first down or two to kick a field goal in the second. It would have been 13-0, and San Francisco would have started smelling the upset.

But after the three-and-out in Green Bay territory, the offense responded with a five-play scoring drive. Greg Jennings’ 57-yard TD catch to give the Packers their first lead at 7-6, and they led the game the rest of the way.

“I think we’re doing some of the things good defenses do in terms of fighting to keep people out of the end zone,” Capers said. “And with our offense, the way we can score points, that’s a good combination because that’s our No. 1 priority is to try to limit those points on the board.”

The defense has answered the call in tough spots throughout the year, allowing only one touchdown after an offensive turnover as opposed to nine a year ago. The defense also allowed the opposition’s four longest kickoff returns and two longest punt returns a year ago to result in four TDs, whereas this year the five kickoff returns of 40-plus yards allowed have resulted in just one TD.

If the unit could have a couple of this year’s adverse situations over again, it would surely like another crack in overtime vs. Miami in Week 6 and at the end of the fourth quarter at Atlanta in Week 12. Against the Dolphins, Miami started its second overtime possession on its own 48 and needed just two first downs to move into field-goal range. At Atlanta with the score tied late, the Falcons started their game-winning drive at the Green Bay 49 after a 40-yard kickoff return and facemask penalty. One first down and a handful of yards more and they kicked a field goal as well.

The margin for error in such instances is always slim, and no defense is good enough to come out on top every time. The two situations this past Sunday vs. San Francisco certainly weren’t as dramatic as the others mentioned, but the defense took the field with the same mentality and they clearly factored into the game’s outcome.

“We know we’ve got to make a stop,” Williams said of the defense’s thoughts in the huddle, though they go unspoken most of the time. “Everyone comes out there with the mindset, ‘OK, let’s make a play, get off the field.’ That’s pretty much the communication right there, and we usually do it.”

Doing so Sunday made for a much more manageable comeback after a slow start, and the Packers won going away.

“To me, that’s one of the biggest differences in our defense this year than a year ago,” Capers said. “We weren’t very good in those situations (in 2009).

“I think our guys have taken a lot of pride in the fact that no matter where they go on the field, they’ve got to find some way to keep our opponent out of the end zone. Again, the things you emphasize, you get, and I think they realize the importance of that. (Sunday) was a good example.”