Here are five things to watch for in the Chiefs game on Sunday against the Chargers:

1. Chiefs red zone offense

While football isn't played on paper, one of the biggest advantages the Chiefs have in regards to trends in this game is when the Chiefs offense has the ball in the red zone.

The Chiefs rank fourth in the NFL in red zone offense, scoring touchdowns on 70.6 percent of the drives that get them inside the opponent's 20-yard line.

Consequently, that's an area where the Chargers defense has struggled this season. The Chargers rank last in the NFL in red zone defense, allowing touchdowns on 75 percent of drives that get deep into their own territory.

The Chargers are tied for the best record in the NFL for a reason—they're a very good football team. But when you play a good team you have to come away with touchdowns when you're close to the end zone, and if the trends hold true in this game, the Chiefs could come away with touchdowns in a game on the road in which they're badly needed.

Chiefs quarterback Alex Smith talked about the success the Chiefs offense has had in the red zone.

"It's all about the execution down there and coach puts us in some good situations," Smith said. "Everything is faster and the windows are smaller. Everything gets magnified down there so it really does come down to the little things, the details and the guys have done a pretty good job of it."

2. Interior pressure – getting Rivers "off his spot"

Whenever you talk to a defensive lineman, his goal isn't always to get sacks but simply to "get the quarterback off his spot."

One area to watch in this game is the matchup on the interior of the Chiefs defensive line, particularly with Chiefs nose tackle Dontari Poe.

Poe has already established himself as one of the premier young defensive lineman in the NFL, and the Chargers will be rolling out their third center so far this season. Season-ending injuries to veterans Nick Hardwick and Doug Legursky have put Rick Ohrnberger in the starting lineup for the Chargers.

At 6-foot-2, 300 pounds, Ohrnberger is giving up a lot of size to Poe, who stands at 6-foot-3, 346 pounds and has two sacks on the season.

Another one of the guys up front who will be trying to get Chargers quarterback Philip Rivers "off his spot" is defensive lineman Jaye Howard, who understands the challenge in front of them on Sunday.

"[Rivers] is playing great right now so it's going to be very important that we keep him contained," Howard said. "He's even running the ball this year so we just have to get to him and get as much pressure as we can."

Rivers is one of the best quarterbacks in the NFL at making plays with guys around him, averaging 8.1 yards per attempt with four touchdowns when under pressure.

The Chiefs face a tough test with Rivers on Sunday.

3. Eliminating big plays on defense

This seems like an obvious thing to watch for, but the Chargers lead the NFL in passing plays of 20 yards or more with 28.

Consequently, the Chiefs defense leads the NFL in fewest completions of 20-plus yards given up with only 11.  

It's strength on strength and if the Chiefs can take away or even slow down the big passing play from the Chargers, they'll be in a much better spot.

It's worth noting that many of the big passing plays from the Chargers come in the form of yards after the catch, where they rank third in the NFL with 766. These yards come from shallow crossing routes from receivers Eddie Royal and Keenan Allen, along with plays made down the field from veteran tight end Antonio Gates and receiver Malcom Floyd.

The angles taken by safeties Husain Abdullah, Ron Parker and Eric Berry, if he's able to play, will be key in this game as they will be forced to make plays in space, something they've excelled at so far this season.

"The key element is making sure they don't get yards after the catch," defensive coordinator Bob Sutton explained of going up against the Chargers passing attack. "They run those crowing routes where they hit guys on the run and they're very good at those. Breaking on the routes and securing those tackles is going to be key for us in this game."

4. Maintaining offensive efficiency

The Chiefs rank in the top five in the NFL in two of the most important offensive statistics: third down conversions and red zone touchdown efficiency.

They rank fourth in the NFL in third-down conversion rate at 50.7 percent and inside the red zone they're scoring touchdowns 70.6 percent of the time.

Whether it's through the air or on the ground, the Chiefs offense will need to be efficient and move the ball against the Chargers defense, both to eat up the clock and also keep the Chargers offense off the field. 

"Obviously you have to take whatever the defense gives you," Chiefs offensive coordinator Doug Pederson said. "Against Denver and New England, they have such great quarterbacks and we did a nice job of keeping Peyton Manning and Tom Brady on the sidelines. We have to do the same thing here with Philip Rivers. But as an offense, you don't worry about that as much as you do your own execution."

One of the reasons the Chiefs offense has been able to stay efficient is because of the different personnel groups they're consistently trotting onto the field. The five skill position players rotate with a different number of running backs, tight ends and receivers on the field at the same time. 

There are always five offensive linemen and a quarterback on the field, but the number of players at each of the skill positions dictates the personnel the defense is going to use on that particular play, and the Chiefs rotate so much that it makes it difficult to game plan against them.

"You would think all of the different stuff is going to give those guys problems to get ready for," Chiefs quarterback Alex Smith said. "Running personnels in and out, putting guys all over the field in different spots. It's fun. I think guys enjoy it.

"I think coach [Reid] does a great job of that—finding guys strengths and isolating those things. So guys have a great time with that. I think for us on offense, we enjoy it. I think we've kind of taken that on a little bit that we can just roll all kinds of personnel's out there and have success with all of them."

5. Game-changing plays

Any time you go on the road and take on a team that's playing at the level the Chargers have so far this season, you need a couple of game-changing plays if you're going to win the game.

They can come in the form of a special team's score, a big turnover or a long touchdown play. But there are always a few plays that stand out in big victories on the road.

In terms of takeaways, the Chargers haven't lost a fumble yet this season and Rivers has only thrown two interceptions, although Sunday would be a great time to add a few more.

One player who has the ability to make game-changing plays any time he touches the football is rookie De'Anthony Thomas, who scored on the first offensive touch of his career, a 17-yard touchdown reception, against the San Francisco 49ers.

Whether it's on offense or a punt return, Thomas will have Chiefs fans holding their breath every time he touches the football.

Thomas grew up in Los Angeles, just over 100 miles from where the Chiefs play on Sunday. "I'm just excited to get back on that field again for my second time," Thomas said on Wednesday. "A couple of family members are going to be there and I'm excited to see them and play for them."