SAN DIEGO — Cairo Santos kicked a 48-yard field goal with 21 seconds remaining, and the Kansas City Chiefs posted a 23-20 victory over the San Diego Chargers on Sunday.

San Diego (5-2) saw its five-game winning streak end. Kansas City (3-3) earned its first AFC West victory of the season.

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

Chargers quarterback Philip Rivers went 17 of 31 for 205 yards, two touchdowns and an interception.

Kansas City running back Jamaal Charles paced all rushers with 95 yards and a touchdown on 22 carries.

San Diego kicker Nick Novak booted a 48-yard field goal with 1:57 remaining to tie the score 20-20. Just over seven minutes earlier, his 24-yard field goal brought the Chargers to within 20-17.

The Chiefs took a 20-14 lead early in the fourth quarter on an 11-yard touchdown pass from Smith to Anthony Sherman. The Chargers had many shots at Sherman, but the plodding tight end was able to shed defenders for the score.

San Diego led 14-10 at the half. Santos’ second field goal, from 40 yards to open the third quarter, cut the Chiefs’ deficit to 14-13.

In the first half’s final minute, the Chargers went ahead after driving 80 yards in 41 seconds. Rivers capped the drive with a 27-yard touchdown pass to Antonio Gates.

It marked the 67th time the tandem combined for a scoring reception, the most of any quarterback-tight end duo in NFL history.

The Chiefs led 10-7 with three minutes left in the half after Santos’ 28-yard field goal. The drive was extended by a costly personal foul committed by linebacker Reggie Walker after an incompletion on third down.

Charles’ 16-yard scoring effort in the second quarter was a zig-zag run that had the Chargers turned in various directions. His rush tied the score at 7, with the drive’s key play being a 26-yard pass from Smith to wide receiver Dwayne Bowe.

The Chargers struck first, and it was from an unlikely source.

Rivers clicked with blocking tight end John Phillips on a first-quarter, 1-yard scoring pass. It was Phillips’ initial catch of the season, a reception that was set up by Malcom Floyd drawing a pass-interference call on backup cornerback Jamell Fleming in the end zone.

NOTES: Chiefs RB Jamaal Charles passed Priest Holmes (6,070) as the team’s all-time leading rusher in the second quarter. Charles finished the day with 6,113 rushing yards. … Chargers CB Jason Verrett, a first-round draft pick this year, was out due to a shoulder injury, his second missed start in six games. He skipped the Jaguars game with a strained hamstring. … San Diego LB Manti Te’o (foot) remains out indefinitely. … Former Chargers DE Leslie O’Neal was inducted into the team’s Hall of Fame at halftime. O’Neal holds the franchise record with 105.5 sacks. … Chiefs SS Eric Berry (ankle) missed his fourth consecutive game.