It was the kindest the 49ers were to their former teammate all night.
Smith struggled against a relentless pass rush while playing the entire first half for Kansas City, even taking a couple wicked shots from the San Francisco defense, and then watched as backup quarterback B.J. Daniels threw a late touchdown pass to give the 49ers a 15-13 victory.
"It was different, definitely different," Smith said. "Those are guys I played a long time with and know very well. There was a lot of talking out there, back and forth from a lot of guys."
It turned out to be a strange reunion for Harbaugh, too.
"It felt a lot like going against my brother," he said. "It was different. It was personal, in the best kind of way. I wish him great success and health. We'll be following him."
Great success and health? Hardly.
Smith was wrestled to the ground at least half a dozen times by the 49ers' defense, the most vicious blow coming in the second quarter, when defensive tackle Tony Jerod-Eddie leveled a helmet-to-helmet hit. He was flagged for a personal foul on the play.
All the pressure prevented the Chiefs from moving the ball the way they did last week in New Orleans, when the No. 1 offense scored a touchdown on its only drive in a 17-13 defeat.
Smith was just 7 of 16 for 62 yards through the air.
"Listen, I expect us to score every time we have the ball," Chiefs coach Andy Reid said. "I don't expect any less than that. So did I expect more? Yeah."
Colin Kaepernick, who took over Smith's starting job in San Francisco last season, only played the first offensive series. He threw just two passes, one a completion for minus-3 yards and the other a misfire toward wide receiver Chad Hall, who was running free to the end zone.
"It was a little overthrown," Kaepernick said. "We got the perfect look."
Colt McCoy and Scott Tolzien alternated series for the 49ers once Kaepernick left, but neither distinguished himself in the race for the No. 2 quarterback job. McCoy threw for 35 yards but also tossed an interception, while Tolzien threw for only 30 yards.
The Chiefs played without Pro Bowl running back Jamaal Charles, who strained his right foot when he stepped on a teammate in practice Monday. Charles worked out before the game and the team considers him day-to-day, though Reid wouldn't discuss his status for next week's game.
"We'll see when we start practice on Sunday how I feel," Charles said. "I'm trying to get my body ready and back in shape."
The main story line, though, was Smith facing his former team.
After leading San Francisco to the playoffs and getting off to a good start last year, he lost the top job when he got hurt. 49ers coach Jim Harbaugh stuck with Kaepernick once Smith was healthy enough to return, and then traded the former No. 1 pick to the Chiefs this past offseason.
Smith has mostly taken the high road when asked about how things went down. And if there was any lingering animosity, it seemed to dissolve when he spoke to Harbaugh before the game.
"The first time I ever played against my former team was in a preseason game and it was a great thrill," Harbaugh said. "I'm sure that he felt that tonight."
Once the game started, it was special teams that provided the thrills.
Demps, who's trying to solidify a job returning kicks for Kansas City, sent the first shock through a meager crowd at Arrowhead Stadium in the first quarter. He fielded a kickoff after the first of Dawson's field goals, found a crease and out-ran the coverage for a touchdown.
The Chiefs haven't had a kickoff return for a score in a regular-season game November 2009, when Charles brought one back against the Pittsburgh Steelers.
"Jamaal Charles? He got some return game?" Demps asked? "I got to get some tips from him."
The 49ers' special teams also shined in the third quarter, when backup linebacker Parys Haralson blocked a punt by Dustin Colquitt. Haralson recovered the ball to set up the second of Dawson's 55-yard field goals -- both of them had plenty of distance to spare.
Those were the 49ers' only points until Daniels hit Chuck Jacobs from 14 yards out with 2:02 left for the go-ahead touchdown, their first touchdown of the preseason after managing only field goals in a 10-6 loss last week to Denver.
Chiefs TE Travis Kelce (bruised knee) and CB Dunta Robinson (shoulder) left the game. ... RT Eric Fisher, the Chiefs' No. 1 overall pick, missed a few plays while getting his hand examined. ... Four of the 49ers' top seven draft picks didn't play due to injuries: DE Tank Carradine (knee), TE Vance McDonald (leg), RB Marcus Lattimore (knee) and DE Quinton Dial (toe). ... 49ers LT Joe Staley was in uniform after missing four recent practices with an undisclosed injury. He had returned to practice Wednesday. ... Haralson also had a sack.