The Kansas City Chiefs face the NFL's top-ranked offense on Sunday in the Pittsburgh Steelers, who have averaged 424.9 yards per game this season.

"They have both the run and the pass game going," Chiefs coach Andy Reid said of the Steelers this season. "[Roethlisberger] is playing well and the runners are playing well. They've got a nice little combination going."

Ben Roethlisberger is currently No. 2 in the NFL with 4,415 passing yards this season, completing 67 percent of his passes with 29 touchdowns and just eight interceptions.

Ben Roethlisberger

"They are a very balanced offense. They like to run and pass the ball," Chiefs cornerback Sean Smith said. "They have a great back, great receivers and a tremendous quarterback who can make all the throws – can take hits and make the throws. So this is by far our biggest test this year."

The Steelers have scored at least 27 points in nine of their 14 games this season, a mark the Chiefs have hit just once.

But the Chiefs also boast the NFL's second best pass defense in terms of yards given up at just 199 per game and have yet to allow a 300-yard passer despite facing Peyton Manning twice, Tom Brady and Philip Rivers.

On the ground, the Steelers are led by running back Le'Veon Bell, who ranks second in the NFL with 1,278 yards rushing and seven touchdowns.

"I watched [Bell] coming out of Michigan State and he is a very versatile back," Chiefs safety Kurt Coleman said. "He is very graceful; he reads his blocks and he is not a guy that is just going to hit a hole. He is going to be patient and allow it to open up and make his one cut. I've seen him make some amazing runs."

Bell also ranks second on the Steelers with 76 receptions for 765 yards and three touchdowns.

On the outside, the Steelers have the NFL's top receiver this season in Antonio Brown, who leads the NFL with 1,498 yards receiving and 11 touchdowns.

Antonio Brown

"I've seen him go against double coverage and beat them," Coleman said of Brown. "He is a handful so we might lose a couple hours of sleep trying to figure out how we are going to stop him. If we can just make them drive the ball down the field every single time they have it, we're giving our offense an opportunity.

"We have to be able to limit the big plays and match up with these guys."

The Steelers offense ranks No. 2 in the NFL this season with 222 plays of 10-plus yards this season. Most importantly for the Chiefs, the Steelers rank No. 1 in the NFL in yards achieved on first down at 6.54 per first down.

For the Chiefs to find success defensively against this potent offense, that will mean getting the Steelers off the field on third down. To accomplish that, the Chiefs will need to create unmanageable third-down situations, which could prove tough if the Steelers average over six yards on first down.

Despite the explosive Steelers offense, Chiefs quarterback Alex Smith doesn't believe that means they should change the way they attack an opposing defense.

"I mean certainly every week we're trying to score more points than our opponent, but for us all of our attention is on the defense," Smith said. "[Steelers defensive coordinator] Dick LeBeau—you can see his handprint, and they do so many unique things that they do and have grown with over the years.

Dick LeBeau

"They're an aggressive defense and they present a lot of problems."

Lebeau, who began his NFL coaching career with the Green Bay Packers in 1976, is known as one of the architects of the zone blitz and Reid spoke of what the Chiefs can expect on Sunday.

"Normally you're going to count on more than four people coming and they could be coming from anywhere so you have to keep your eyes open," Reid said. "At the same time, you have to play your game."

One area the Chiefs can try and take advantage is in the running game, where the Steelers have allowed 50 runs of 10-plus yards this season, which ranks 28th in the NFL.

The Steelers rank 27th in the NFL with just 24 sacks this season, but there's plenty of talent along that defensive front with Cameron Hayward and James Harrison, among others.

In the defensive backfield, cornerback William Gay is a player to keep an eye on. Gay has three pick-sixes this season and is a gambler, routinely breaking on routes and going for the big play.

When combined with a zone-blitzing defensive coordinator, Gay has made his fair share of game-changing plays for the Steelers defense.

But Smith and the Chiefs are ready for the challenge.

"You've been working hard to put yourself in this position," Smith said on Wednesday. "You wanted the stages to get bigger and bigger and be more meaningful and here we are.

"Embrace the entire week of preparation, embrace today and go out there on Sunday and have fun and enjoy it, enjoy each other and go out there and compete." A win on Sunday for the Steelers means they're in the playoffs, while a win for the Chiefs will earn them the right to host the San Diego Chargers next week at Arrowhead Stadium for a spot in the playoffs.