INGLEWOOD, Calif. — In a game defined by calculated risks, the one decision exempt from debate is Kansas City linebacker Melvin Ingram’s coin-toss choice.

Ingram selected tails as his team and the Los Angeles Chargers prepared for overtime, with the score 28-28. The coin landed tails-side-up on the artificial turf at SoFi Stadium, giving Kansas City the ball. Six plays later, Travis Kelce scored a walk-off touchdown, a result that allowed Kansas City to win, 34-28, and prevented Chargers coach Brandon Staley from perhaps finally winning an aggressive gamble.

“My hat goes off to Melvin Ingram,” Kansas City Coach Andy Reid said with a smile at a postgame news conference.

Kelce’s overtime touchdown came from a short pass Patrick Mahomes fired on an in-breaking route. After catching it, Kelce repositioned his body and then sprinted down the field 34 yards, weaving through defenders as his teammates blocked for him. Victory in hand, he lifted his arms in a celebratory shrug motion.

Ingram’s luck, Kelce’s score, and second-half bursts from Mahomes and Tyreek Hill solidified Kansas City (10-4) at the top of the A.F.C. West, and also propelled them to a seventh consecutive win. For the Chargers (8-6), it raises questions about the team’s play-calling philosophy. Instead of kicking modest field goals, Staley elected to go for it five times on fourth down, converting only two of them. Had they made a field goal in even one of those instances, the Chargers very likely would have won.

“That’s going to be the mind-set no matter who we play,” Staley said. “I felt really comfortable with all of those decisions.”

For Kansas City, the defensive showing highlighted a resurgence for the unit that had been one of the N.F.L.’s worst in the first half of the season. At 3-4 through Week 7, the defense on average surrendered 404 yards a game, putting the offense in precarious spots that forced Mahomes to take unneeded risks. But it rebounded, and entering Thursday’s game, Kansas City had not allowed an opponent to score more than 20 points during its streak.

Los Angeles presented a true barometer, though, as some of the opponents during that stretch — the Giants, Broncos and Raiders — were clearly worse teams, and the Packers and Cowboys played short-handed with key players unavailable. But the fourth-down stops illustrated growth, and they came in variety.

A pass breakup by Daniel Sorensen. A pass deflection by Nick Bolton. An unsuccessful first-quarter touchdown pass. The moments preserved points, which linebacker Anthony Hitchens said was costly for the Chargers.

“No disrespect, but that’s just their game plan,” said Hitchens, who also caught an interception. “They don’t want to kick field goals, they want to go for it, then we have to make them pay.”

The Kansas City offense, compared to the standards it set by winning the A.F.C. in back-to-back seasons, had also underwhelmed. Once an intimidating juggernaut, the unit this year seemed mortal. Following the blueprint Tampa Bay deployed in the Super Bowl, teams have used two-high safeties to combat Kansas City’s downfield strikes, forcing them to be disciplined in their approach through running and shorter passes.

Through Week 12, opposing teams used two-safety lineups on 72 percent of Kansas City’s offensive snaps, according to NextGen Stats. That is by far the highest rate in the league — teams against Buffalo used that grouping only 57 percent of the time. The Chargers used variations of that strategy in the first half, limited Mahomes to 112 yards, and Los Angeles led, 14-10.

Things changed in the third quarter, though, when the Chargers’ versatile safety Derwin James aggravated a hamstring injury and did not re-enter the game. An offensive teammate, tight end Donald Parham, also sustained a gruesome injury after dropping a fourth-down pass in the end zone in the first quarter. As he landed, his head hit the ground and his body stiffened. Officials paused the game for about 15 minutes while they put him on a stretcher, and he underwent tests at a hospital. Officials said he was in stable condition.

“Any time that you see that live and you’re close to it, it impacts you,” Staley said of continuing to coach while managing his emotions after the injury. “At the same time, we’re trying to play for him the rest of the way. That’s what our guys did tonight, they laid it on the line and played a whale of a game for him. I hope that he’s proud of that.”

Two plays in particular doomed Los Angeles — a 32-yard scramble by Mahomes in the fourth quarter and a 69-yard catch-and-run by Kelce in the fourth. Those moments directly led to touchdowns, the fourth-quarter scramble setting up a 7-yard touchdown toss to Kelce to tie the score at 28-28. Kelce finished with 191 yards and two touchdowns, a rebound after not scoring a touchdown in his previous four games.

Mahomes, who threw for 410 yards, connected on a 40-yard pass to Hill in the third quarter, but misfired on a potential touchdown to Mecole Hardman. But he later found Hill, who finished with 148 receiving yards, on a 1-yard touchdown.

Kansas City complemented the explosive sequences with two successful drives consisting of 10 and 11 plays. That balance, Mahomes said, should keep other teams honest.

“We’re always going to have the chance to make the throws on the field to Tyreek and Mecole and all that different type of stuff,” Mahomes said. “But if we can show everybody that we can drive down the field methodically with patience, that’ll be hard for defenses to stop.”

But the Chargers competed well against Kansas City as they normally have. In their eight meetings since 2018, seven of them were decided by 10 points or less. The outlier was Week 17 last season, when Kansas City rested many its starters having already secured the conference’s top seed. In September, Los Angeles beat them similarly with a last-second touchdown.

They had their chances on Thursday amid strong performances from their stars. Justin Herbert threw for 236 yards, two touchdowns and an interception, and the team collectively rushed for 192 yards and two scores.

The decisions on fourth down remained questionable to some, but were not uncharacteristic. The Chargers have been successful on 14 of 25 fourth-down attempts, and have now alerted the rest of the league in prime time that they are unafraid of the consequences.

With a likely playoff push ahead of them, it appears that trend does not appear to be stopping.

“I think that’s a statement of trusting everyone on the field and off the field,” Herbert said. “We love to be put in those situations. Unfortunately, we didn’t convert as many as we would have liked to have today, but we’re going to ride with each other and we’re going to be right back.”