While we should have seen it coming given their run to the playoffs and the dismantling of the Cincinnati Bengals that followed, somehow the San Diego Chargers snuck up on everyone again.

Is it all smoke and mirrors? Or is this team far better than we realize?

Is this team a Super Bowl contender?

This is a team which lost Ryan Mathews in Week 2, has an offensive line which continues to struggle and a defense with some problems rushing the passer.

Yet for the last four weeks, the Chargers have won each game and looked impressive doing it.

The genius of San Diego -- and really of any team that aspires to greatness and has a chance to achieve it -- is its ability to overcome the issues it is faced with.

All the credit in the world goes to head coach Mike McCoy, and if some of the success quarterback Philip Rivers has had seems familiar, that's because McCoy arrived in San Diego by way of Denver and the Broncos.

A year with Peyton Manning certainly capped off an interesting -- and flexible -- stint with the Broncos as McCoy worked with Kyle Orton, then Tim Tebow and finally Manning. Such a diverse group of quarterbacks helped hone McCoy's skills and kept him versatile, a trait which has helped him revitalize Rivers' career and overcome some of the issues on offense.

Issues such as a continually lackluster offensive line and the injuries to his two starting running backs, Ryan Mathews and Danny Woodhead.

In 2012, prior to McCoy's arrival, the Chargers offensive line was ranked No. 22 on NFL.com and No. 28 by Pro Football Focus.

By the end of the 2013 NFL season, the Chargers were tied for No. 6 on NFL.com and had moved up to No. 18 on Pro Football Focus. 

What (aside from McCoy) was the change? It wasn't personnel which, aside from Jeromey Clary who was replaced by Johnnie Troutman, is the same in 2014 as it was in 2013 up until Nick Hardwick got injured. Even this year, the offensive line isn't exactly lighting the world on fire. 

Pro Football Focus has graded every offensive lineman but King Dunlap with a negative grade -- with Troutman into negative double digits (-14.1). While offensive line grades are difficult to get right (we don't really know what a blocking responsibility is, we can only make educated guesses), it doesn't take intricate knowledge of schemes to know that Rivers is hit far too much.

So how does an offense which allows its quarterback to be hit as much as this one does still function?

A lot of short, quick passing routes. According to Pro Football Focus, the Chargers threw in the short middle of the field (under 10 yards) 47 times, completing 36 of them for 309 yards. Yes, the offense is effective at all levels of the field -- Rivers has thrown for 194 yards in the intermediate middle of the field (between 10 and 20 yards) and 150 yards in the deep middle (20+ yards).

But the slants and crossing patterns McCoy used in Denver are present in San Diego and you can see that in the statistics even if you aren't watching the game.

The offense also has no issue throwing into the flat or on a screen -- in fact Rivers is 29 for 29 in passes behind the line of scrimmage. That may not seem like much but all you need to do is watch your average NFL game and you will see dropped passes and badly thrown balls aplenty behind the line of scrimmage.

When Rivers needs to dump the ball, he dumps it wisely and effectively.

In Rivers, McCoy has found a player similar to Manning -- a precise and smart quarterback who can get the ball out quickly in the face of pressure. That goes a long way toward negating any pressure he sees. If the defense blitzes, Rivers hits that short slant or the screen pass and it's off to the races. All it takes is one big run after the catch and the defense needs to stop trying to pin his ears back and watch the edges and middle of the field.

Rivers
Phillip Rivers thrives under the blitz. (Getty Images)

When Rivers is under pressure, his quarterback rating is 94.7, but it rises to 125.3 when he feels no pressure. 

Ready to have your mind blown? 

Rivers' quarterback rating goes from 94.7 under pressure to 110 when he is blitzed. So it's harder for him when the pocket just collapses, but if you send the house after him, he actually plays better.

Again, that's all about a quick release and multiple targets of opportunity.

This makes it very hard for defenses to stop him. If they blitz (as the New York Jets tried last week), they can be carved up but if they sit back too much and can't generate a pass rush without a blitz (as the Seattle Seahawks struggled with at times in Week 2), then Rivers will find the seams in the secondary and go to town anyway.

In fact, part of the reason the Chargers lost in Week 1 against the Cardinals is because the receivers dropped too many balls. Antonio Gates dropped two (including a big first down), Keenan Allen dropped a pair, as did Eddie Royal.

Contrast that to the one dropped pass against Seattle, the one against Jacksonville and none against either the Jets or Buffalo.

That's the difference between losing by one point to Arizona and winning the next four games by a score of 116-45.

So is a very underrated defense -- especially in pass defense.

Last year the Chargers were among the worst in the NFL in pass coverage, ranked No. 29 by NFL.com. The bright side to that was the defense only allowed 23 passing touchdowns -- good for the 12th least in the league. Unfortunately, they only totaled 11 interceptions which was the 26th worst in the NFL.

This year the Chargers pass defense is ranked No. 2 (through five weeks), with a 2 to 1 touchdown to interception ratio.

Unlike the offensive line turnaround this one has a lot to do with personnel. 

For too long the Chargers secondary consisted of safety Eric Weddle and some group of guys who were nowhere near in Weddle's class.

This year the Chargers picked up Brandon Flowers in free agency and drafted rookie corner Jason Verrett. Verrett had a great Week 1 against the Cardinals but has struggled since with hamstring issues.

Despite that, he is still rated as Pro Football Focus' No. 16 cornerback. Flowers, meanwhile, has been ridiculously good and is the top-rated corner after five games and with two interceptions to his credit.

Weddle is joined at safety by Jahleel Addae who has only just become a starter but has played very well on a rotational basis prior.

Between a revitalized offense and an improved defense, the Chargers have already shown this year that they are ready to run with the big boys.

Or are they?

The problem with all these stats -- and even with watching all the tape from the previous five games -- is that the Chargers have only really met two legitimate contenders.

The Cardinals and Seahawks both have good offenses and defenses and both of those were well-fought games. As we have already, you can argue that the Chargers had a big hand in beating themselves in Week 1 and had they not dropped multiple passes, might have won the game.

And of course, any time you manage to beat the Seahawks is worth applause.

The rest of the wins aren't nearly as impressive. The Bills have been terribly inconsistent and were coming off an emotional division win over the Miami Dolphins. The Jaguars have been terrible this year and the Jets were starting an implosion the likes of which we hadn't seen since the last Jets implosion.

It's impossible to read too much into the games over the last three weeks, and this week's match won't change that as the Oakland Raiders are a bad team -- even at home.

It won't be until the Chargers see the Chiefs in Week 7 that we begin to get a real sense of this team, followed by a true test of the team's mettle in Week 8 when they head to Denver to play the Broncos.

Last season, the Chargers were the one team (before the Seahawks in the Super Bowl) which managed to stifle the Broncos offense. In all three games, the Chargers took the ball and kept it, grinding the clock and keeping Manning off the field. 

This year the Broncos have added a potent receiving threat in Emmanuel Sanders and two hard-hitting defenders in the persons of Aqib Talib and T.J. Ward.

Overcoming the Broncos defense will be hard and while the Chargers might try and diffuse the pass rush of DeMarcus Ware and Von Miller with those short slants we just talked about, it could be harder with Ward and Talib delivering hits across the middle.

The Denver Broncos seem to present the biggest challenge in the AFC right now.

Looking around the rest of the conference, it's easy to see the AFC Championship is there for the taking. Certainly the New England Patriots have looked more vulnerable than ever before and the Cincinnati Bengals showed some huge flaws in the loss to the Patriots last week. The Indianapolis Colts have too many holes on defense to really be on the same level as what the Chargers appear to be, though Andrew Luck is the great equalizer.

The Broncos don't seem to have too many weak points though, despite struggling for three quarters against the Seahawks in Seattle back in Week 3.

Are the Chargers legitimate Super Bowl contenders? Can they win the AFC and head to Arizona to face the best the NFC has to offer?

The truth is, given the quality of the teams they are beating up on right now, we don't know. 

But we will soon enough, when Week 8 rolls around and it's do or die time in Denver.