SAN DIEGO — On the Chiefs’ previous San Diego visit, the Kansas City kicker missed a game-winning field goal in the closing seconds.

Not so this time.

Cairo Santos booted a 48-yard field goal with 21 seconds remaining, and the Chiefs posted a 23-20 victory over the Chargers on Sunday.

San Diego (5-2) saw its five-game winning streak end. Kansas City (3-3) won for the third time in four games.

Last year, Ryan Succop misfired from 41 yards with four seconds left in a game the Chargers won in overtime.

The Chargers weren’t as fortunate this time, losing for the first time this season at Qualcomm Stadium, with a rookie delivering the decisive points.

“I felt like he was going to make it,” said Chiefs coach Andy Reid, who now owns a 14-2 record the week after his team has a bye. “He was due for an opportunity like this.”

The Chiefs came out on top thanks to their work on third downs.

The Chargers were a dreadful three of 10 as their offense hit a rare speed bump. Conversely, the Chiefs converted half of their 14 third-down chances.

“It’s both sides of the ball,” Chargers quarterback Philip Rivers said. “The defensive guys will tell you they have to get off the field, but we were saying offensively, we got to get first downs. Our defense was out there tired and fighting like crazy. … We got to help them out.”

The Chiefs dominated the time of possession, hogging the ball for 39 minutes of the 60 minutes.

“Sometimes the best defense against Philip Rivers is keeping him on sideline,” Reid said. “We were able to do that for the most part in that third quarter.”

Chiefs quarterback Alex Smith completed 19 of 28 attempts for 221 yards and a touchdown.

Rivers went 17 of 31 for 205 yards with two touchdown passes and an interception.

Kansas City running back Jamaal Charles paced all rushers with 95 yards and a touchdown on 22 carries. Charles passed Priest Holmes (6,070) as the team’s all-time leading rusher in the second quarter, finishing the day with 6,113 rushing yards.

“It was a big win,” Charles said. “That was an amazing game to pull off today.”

The Chiefs’ go-ahead drive was aided by a facemask call on defensive end Corey Liuget when he brushed against Smith’s helmet.

“I don’t believe I did, but the referee called it, so it’s a facemask if he called it,” Liuget said. “In the books, that’s what went down.”

What the Chiefs said:

“I think that the team is in a good place mentally. We took this challenge on, and with no one giving us a chance.” — Chiefs quarterback Alex Smith, on the significance of Sunday’s win.

What the Chargers said:

“The big thing about all this is that it is a short week so we don’t have time to feel sorry about ourselves. I know Denver doesn’t care.” — Chargers linebacker Dwight Freeney, on how quickly Sunday’s loss to Kansas City must be forgotten with San Diego set to play the Denver Broncos on Thursday.

What we learned about the Chiefs:

1. The Chiefs stole a page from the Chargers’ playbook and played keep-away. By hogging the ball for 39 minutes, Kansas City kept San Diego’s best weapon, quarterback Philip Rivers, on the sideline. The Chiefs have some decent weapons outside, especially wide receiver Dwayne Bowe, but they leaned on their primary option, which is running the ball. Kansas City’s 154 rushing yards were the most allowed by the Chargers this season.

“We didn’t have 11 guys making plays,” Chargers coach Mike McCoy said. “We didn’t stop them.”

2. The Chiefs avoided getting buried in the AFC West. If Kansas City lost, it would have fallen to 2-4, and any aspirations of winning the division by overtaking the Chargers and Denver Broncos would have been farfetched. However, the win Sunday will make for a more interesting second half of the season. “It was big,” Bowe said. “It was enormous.”

–QB Alex Smith beat the Chiefs for the first time as a pro. However, it wasn’t his first win in Qualcomm Stadium, as he won two San Diego prep titles at the venue when playing for Helix High. Smith finished 19 of 28 for 221 yards and a touchdown.

–WR Junior Hemingway left the game with a leg injury.

–OLB Justin Houston collected his seventh sack of the season, which leads the Chiefs.

What we learned about the Chargers:

1. The Chargers are fond of saying “next man up,” but it could be catching up with them. With linebacker Manti Te’o out again and others nicked up, San Diego’s run defense was pushed around with regularity. The Chargers have to hope they can fix what ails them in the running game quickly, otherwise the blueprint will be out on how to beat the team. “We’re a no-excuses bunch,” safety Eric Weddle said. “We man up to our mistakes, and we just didn’t get it done today.”

2. Quarterback Philip Rivers is human. After an NFL-record run of five consecutive games with a passer rating of at least 120, a stretch that coincided with the Chargers’ five-game winning streak, Rivers was a tad off Sunday. His passer rating was 83.4, the Chargers were unable to compensate for his so-so performance.

“It’s a compliment that y’all expect that every week, but I think it’s unrealistic,” Rivers said. “That’s why it had never happened before, what happened in the last five weeks. In every game you want a few throws back, but it was not our best, but it was not an awful performance. It was one in which we had a chance to win and we just didn’t do it.”

Rivers, who entered the game with the NFL’s highest passer rating, completed 17 of 31 passes for 205 yards with two touchdowns and an interception.

–CB Brandon Flowers practiced only once in the days leading to the game against the Chiefs. However, he wasn’t going to sit out Sunday after spending his first six seasons with the Chiefs; he signed with the Chargers as a free agent last offseason. However, Flowers, who was the last player introduced before the game, was concussed in the second quarter and didn’t play in the second half. He finished with three tackles in his limited stint.

–ILB Kavell Connor will continue to start for Manti Te’o, who remains out with a foot injury. The Chargers haven’t given a timetable for Te’o’s return, but with Connor and others had a tough time defending the run Sunday.

–CB Shareece Wright returned to the starting lineup after missing two games with a knee injury. He was credited with eight tackles.