SANTA CLARA, Calif. — Coming off their most exciting win of the season and engulfed in speculation that their players and coaches were drifting apart, the San Francisco 49ers encountered something Monday that got their undivided attention.

The Kansas City Chiefs’ nationally televised blowout of the New England Patriots.

“(We) understand how good the Kansas City Chiefs are,” 49ers coach Jim Harbaugh said Wednesday as his team began preparations for Sunday’s home game.

The 49ers haven’t played the Chiefs in four years. Those who were around for that one undoubtedly recall the shellacking — 31-10 in favor of Kansas City.

Running back Jamaal Charles, star of the Chiefs’ 41-14 pounding of the Patriots on Monday with three touchdowns, was one of Kansas City’s standouts that day as well.

Harbaugh didn’t need to be reminded of Charles’ brilliance.

“Great challenge for us this week,” he said. “Great speed back. Elusive back. Power back. Tremendous hands. Got all the feel and instinct of a tremendous back. Real feel for the screen game …

“Just A-plus across the board.”

Charles won’t be the first great back the 49ers will have faced this season. He merely completes a Murderer’s Row that also featured Dallas’ DeMarco Murray, Chicago’s Matt Forte and Philadelphia’s LeSean McCoy.

The results got progressively better. After giving up 118 rushing yards and a touchdown to Murray in the opener, the 49ers limited Forte to a total of 36 yards (21 rushing, 15 receiving) in Week 2 and McCoy to just 17 rushing yards and no receptions last week.

Bring on Charles? Harbaugh won’t be that boastful.

“Our team is very focused,” he said. “We understand it’s a big game, big challenge ahead of us. Big task.”

Meanwhile, several 49ers players went on the defensive this week in support of Harbaugh in the wake of reports Sunday and Monday by national analysts Deion Sanders and Trent Dilfer that he is losing his team and the team chemistry is approaching a toxic state.

“Last I checked, I was in the locker room and it was all smiles and everybody was happy,” outspoken guard Alex Boone said. “Have you not seen (Harbaugh’s) energy? He’s exciting 24/7. You’ve got to love playing for a guy like that. That’s what’s football is all about.”

Sanders, who shares an agent with 49ers receiver Michael Crabtree, went out of his way this week to insist that his friend is not his source of the locker-room discontent.

Crabtree found himself having to do the same Tuesday, tweeting: “I don’t know what people are talking about with Mr. Deion, but we good over here.”

Quarterback Colin Kaepernick considers the alleged friction a non-issue.

“I’d like to know who the source is,” he said, “so when you get a

source from that, then we can talk about that.”

NOTES: TE Vernon Davis (back) did not practice Wednesday, but he said he felt a lot better. … TE Vance McDonald (knee) returned to practice after missing the past two games. … OT Anthony Davis had an MRI on his knee, which was injured in Sunday’s win over the Philadelphia Eagles. No damage was found, but Davis did not practice Wednesday. … CB Tramaine Brock (toe) did not practice Wednesday.