By Matt Williamson | ESPN Insider

The Carolina Panthers came into San Francisco on Sunday and won 10-9 in a physical, grind-it-out football game. It's the type of game this team simply hasn't won the past couple of seasons. Carolina's defense was fantastic and the offense under Cam Newton did enough to win. The Panthers have now won five in a row, are 6-3 overall and find themselves in the thick of the NFC South race and overall playoff picture.

Are the Panthers for real? And can this exceptional defense carry them to the playoffs?

Newton had shown a lot of improvement coming into this game and the Panthers will always show a dedication to their diverse power running game under offensive coordinator Mike Shula. But as he has displayed for much of his career, Newton's accuracy can come and go -- and on Sunday it took a step backward, as he registered a 19.3 Total QBR and completed only 50 percent of his passes. He still relies far too much on just his upper body when throwing the ball, and in turn his passes can sail and lack repeatable accuracy because of an inconsistent base. Of course Newton still needs much work on his fundamentals, but he has a cannon for a right arm and gets away with his deficiencies much more than a less talented quarterback would. He is also improving from a mental perspective, not trying to force too many throws and throwing the ball away if nothing is there.

Newton happens to be an elite running threat as well, which gives the Panthers a rare luxury of having four ball carriers with a variety of strengths to their game in Newton, DeAngelo Williams, Mike Tolbert and Jonathan Stewart, who looks fully healthy for the first time in recent memory. Shula has kept it simple for Newton, calling more run plays and simple passing plays, but if it wasn't for one of the league's best defenses this strategy wouldn't be possible.

Luke Kuechly, last year's defensive rookie of the year, has already emerged as one of the league's truly elite linebackers and this is his 4-3 defense. Comparisons to greats such as Patrick Willis and Ray Lewis are not too far-fetched in terms of expectations for Kuechly's career, as he simply excels in all areas of playing the position. Kuechly is a great blitzer, rarely takes a false first step to the ball and is a tremendous tackler (11 tackles on Sunday). But for as great as Kuechly is -- his counterpart on the second level, Thomas Davis, is also one of the top linebackers in the league -- it all starts up front for the Panthers' defense.

This might be the best front seven in the NFL and Carolina's defensive line ruled the day Sunday against what is often considered one of the league's best and most physical offensive lines. The 49ers' running game is extremely difficult to prepare for and play against because of the variety of personnel and formations they can throw at you. Frank Gore did have an impressive day (16 carries for 82 yards), but the Panthers did a good job tackling. As ESPN Stats & Information noted, the 49ers were limited to 44 yards after contact on 32 rushes and receptions Sunday, their lowest of the season. Carolina's defensive ends also did a great job limiting Colin Kaepernick's scrambles, as it was the first game this season Kaepernick didn't have a scramble.

But the bigger difference in the game was that Carolina's pass rush was simply overwhelming. Kaepernick was under pressure on nearly every snap and was sacked six times. Carolina did a lot of blitzing, but also consistently got into the backfield when rushing just their four-man defensive line. The Panthers could have back-to-back defensive rookies of the year, as Star Lotulelei is playing as well as any rookie in the league on that side of the ball.

Lotulelei is a big, powerful player who frees up everyone around him but also shows penetration skills. The addition of second-round pick Kawann Short also can't be overlooked, as Short is much more of the traditional upfield three-technique. While these two rookie defensive tackles complement one another very well, the ends were already stars -- even though Charles Johnsonand Greg Hardy are not household names to many fans. Both are stout at the point of attack, but more importantly they consistently beat the offensive tackles across from them in the passing game. Six different Panthers defenders registered at least a half sack Sunday. Entering the season, the biggest question to me on the defensive side of the ball was the Panthers' secondary.

Of course this group benefits a great deal from this front seven and the pass rush it generates, but it is playing very well in its own right. Carolina is much better off at safety now with the additions of Quintin Mikell and Mike Mitchell, both of whom have revived their careers with the Panthers. The same can be said for Drayton Florence at cornerback, while Captain Munnerlyn is an undersized, but tough CB who is having a good season. This defense, and the secondary specifically, was exceptional on third downs in against Kaepernick, allowing only 2-of-13 conversions. This is notable, as San Francisco had been efficient on third downs coming into this game. When factoring lost yardage to sacks, the 49ers had just 46 passing yards in San Francisco. But the Panthers will not face passing games that are ailing as much as the 49ers' is right now every week. Carolina hosts the Patriots next week with New England having two weeks to prepare. That will be a great test for the Panthers' defense.

Looking ahead to the playoff race, the Panthers match up well against the Saints, who are still on the schedule twice in the second half of the season. Those contests should ultimately decide the NFC South champion. Carolina's defense is much better against the pass than run, but the Saints are not going to beat anyone on the back of their run game. As we saw when the Saints visited the Jets in Week 9, New Orleans is a team that be pushed around on both sides of the ball. The Jets ran all over the Saints in a physically dominating fashion, with New Orleans missing tackle after tackle en route to giving up 198 yards on the ground. Carolina could do exactly the same thing.

At this point, it would be a shock if the Panthers didn't end up in the postseason, and they have a great shot of winning the NFC South. This team is built very much in the same way as San Francisco and Seattle, albeit a year behind in the process. Ron Rivera and this organization have a distinct plan for winning football games behind a strong defense and a power running game and they are a difficult team to play against right now. If Newton can continue to protect the football, this team will be a tough out in the playoffs.