Here are five keys to the game heading into Sunday's season opener between the San Diego Chargers and Kansas City:

1. Keenan Allen vs. Marcus Peters – Keenan Allen is a 24-year old who established himself as one of the game's premiere wide receivers in an injury shortened 2015 campaign.  Marcus Peters is a 23-year old cornerback who made the Pro Bowl as a rookie last season after leading the NFL with eight interceptions.  It goes without saying that all eyes will be on this marquee matchup.  Allen hasn't faced the Chiefs since 2014 as he missed both meetings last season with a kidney injury. However, he has had success against KC, catching 20 passes for 271 yards in three career games.  KA13 says he is eager to face the AFC West foe, and knows he is in for a handful when lined up against Peters:

"I'm definitely excited to play against the Chiefs again and go back to Arrowhead.  It will definitely be fun.  Those fans get loud.  And to go against Marcus Peters, he plays the quarterback really well and has good ball skills.  If I'm not on my game, he'll make me pay."

2. Jeremy Maclin vs. Jason Verrett – On the flip side, there is an equally premiere matchup when the Chiefs have the ball.  Jeremy Maclin caught a career-high 87 passes for 1,088 yards and eight touchdowns in his first season with the Chiefs last year.  Odds are he'll see his fair share of Jason Verrett, who is fresh off a Pro Bowl campaign heading into his third season. Verrett has a lot of respect for the Chiefs' top weapon after lining up opposite him in 2015.  He explained how he is in for a tough test:

"Maclin is a good receiver. He is physical at the line of scrimmage, but I'm looking forward to the matchup.  He was tough last year.  He likes to battle, and I really like his game.  What stands out is how he is a physical receiver, and Alex Smith is really consistent in what he does with him."

3. Beware of Backfield Duo – It is possible that Jamaal Charles will play on Sunday, but Chiefs Head Coach Andy Reid said he doesn't think that will be the case. Either way, the Chargers will have their hands full stopping the run. Spencer Ware and Charcandrick West were a dynamic duo a year ago for Kansas City. Ware had 72 carries for 403 yards and six touchdowns while West had 160 for 634 yards and four TDs. Both players were effective against the Bolts as Defensive Coordinator John Pagano compared them to Branden Oliver:

"We've got to tackle better. We've got to tackle as a unit and we've got to get those guys down on the ground. They are both great runners where they have great balance, strong lower bodies; they remind you a little bit of BO Oliver….One is more of the inside type of slasher, and the other has the potential to get it to the edge. I think they are both great backs. I think they are a great one-two combo for the things that they do. They have great balance."

4. Can't Settle for Three – Points figure to come at a premium against a traditionally stout defense, so San Diego can't settle for field goals. While 2015 is in the past, Philip Rivers brought up how the Chargers were only able to muster a single field goal in each of their meetings against the Chiefs. However, Philip Rivers was quick to point out how this year's offense will look different than what KC saw last season:

"We're definitely trotting a different offense out there. Obviously we have Keenan healthy and we have Melvin (Gordon) healthy. We're different up front in the sense that it's a (new) center, and I don't even remember where we were at that point in the shuffle last year. You throw in Travis (Benjamin), Tyrell (Williams) and Dontrelle (Inman), with (Antonio) Gates and Hunter Henry; we're certainly a different team as well than we were when we went in there last year and played them at home. But we scored six points all of last year. I believe in our defense, but I believe it will take more than a field goal to win. So we have to certainly play better than we have the past two times against them."

5. Overcome Arrowhead – Arrowhead Stadium is one of the toughest places to play in the NFL, but also one of the most historic. Known for having deafening crowd noise, Rivers expects it to be as loud as ever for the season opener to give the Chiefs a home field advantage:

"It's one of the best in the whole NFL. It's arguably as loud as any place; Seattle is the only one that comes to mind that you can argue is louder. But it's awesome. To me it's old school, NFL atmosphere. They have great fans and it's a great place to play."

Head Coach Mike McCoy backed up Rivers' assertion

"Arrowhead is one of the great stadiums in all of sports. Their fan support, tradition, history; you've got to go in there and play your best because if you don't you're not going to be able to hear. So you've got to go in there and perform at a certain level. You just love their fan support. It's a great place to play."