Andy Reid and Patrick Mahomes are nemeses to many in the NFL based on the Chiefs’ track record of success approaching historic levels. Count the Chargers among the division rivals failing to live up to their end of the rivalry in recent years.When they meet Sunday at Los Angeles, Kansas City (3-0) seeks a sixth consecutive win over the Chargers (2-1) as the home team introduces first-year head coach Jim Harbaugh to what has become a one-sided AFC West fight with Reid and Mahomes. Turning the tables won’t be easy.”Multiple challenges,” Harbaugh said of facing the Chiefs before Los Angeles enters its bye week. “Really good run game, really good throwing game, explosive offense. I think everybody understands the challenge of playing a quarterback like Patrick Mahomes in every way. His ability to move the ball with his legs, with his arm, within the offense is elite.”Modest statistical production to date is becoming a hot topic outside of the Chiefs’ locker room. Kansas City is 14th in the NFL in total offense (328 yards per game) and the usual lead receiver, perennial Pro Bowl tight end Travis Kelce, is off to an admittedly slow start with eight receptions for 69 yards and no touchdowns in three games.He’s one reception from tying Tony Gonzalez for the franchise record with 916 catches, and Kelce’s next TD catch from Mahomes would break a tie on the NFL’s all-time list with Drew Brees and Jimmy Graham of the Saints for third-most QB-TE touchdown connections. But Reid said the narrative of Kelce being “old” or “distracted” is false.”Defenses don’t think that,” Reid said. “We have another receiver who plays opposite him that has a lot of yards and catches. That’s how this thing goes. Travis is fine. He’s being Trav. He works his tail off. He hasn’t lost a step and all those things. He’s not distracted. People are making sure they have him taking care of, these defenses.”Chiefs wide receiver Rashee Rice is working through an ankle injury while starring as Mahomes’ featured target in September with an NFL-high 24 receptions for 288 yards and two touchdowns. Mahomes has completed 69.6 percent of his passes for 659 yards, five touchdowns and four interceptions through three games.The Chargers present a hefty challenge with a defense ranked in the top 10 in scoring defense (11 points per game, third), yards per game (267, sixth), run defense (91.7 per game, sixth) and pass defense (175.3 per game, 10th).”It’s a physical football team, both sides of the ball,” said Reid, who has a record of 17-5 against the Chargers since taking over the Chiefs in 2013. “You’ve got to be ready for a complete game. Their defenses are going to give you a variety of looks. One of the top defenses in the NFL right now.”Mahomes will look across the line at a defense with a few missing pieces. Pass rusher Joey Bosa (hip) and linebacker Junior Colson (hamstring) sat out Wednesday’s practice. Safety Derwin James Jr. was suspended for Week 4 after being penalized for unnecessary roughness at Pittsburgh.Elijah Molden or A.J. Finley will get the start — along with Alohi Gilman — at safety against the Chiefs.”He genuinely cares and does not want to hurt anybody,” Harbaugh said of James’ one-game ban from the NFL. “He wants to do it the way the league wants it done and the evidence is there.”It will be next man-up mentality.”