Chiefs quarterback Patrick Mahomes (15), who ran when needed against the Chargers, climbs past linebacker Troy Dye (43).

(Gina Ferazzi/Los Angeles Times)

A thrilling fourth quarter that led to a season-opening victory gave hope that this era of the Chargers could be different from other teams of the past. Two real-life losses have shown that old habits die hard.

The Chargers went scoreless in the second half Sunday for the second straight game while blowing a 10-7 halftime lead.

Herbert, who left last week’s game in Pittsburgh with an ankle injury early in the third quarter, lamented the offense’s struggles on third and fourth downs against the Chiefs.

The Chargers were 4 of 13 on third downs and failed on a fourth-and-one from the Chiefs’ three-yard line in the fourth quarter of a tied game. The team has gone seven to 24 in its last two games with third losses.

The Chiefs, who have yet to become an offensive juggernaut in recent years, converted nine of 16 (56.3%) of their third-down attempts, a season high.

“They’ve gotten better at playing situational football,” outside linebacker Khalil Mack said. “Other years there would be some kind of glitch here, a glitch there and they could score over 20 points. Today seemed a little more difficult for her.”

The Chargers, who have lost six straight to their AFC West rival, largely prevented Chiefs quarterback Patrick Mahomes from making game-changing plays.

The two-time NFL Most Valuable Player had 12 rushing yards on five carries. But while he threw for 245 yards, with a touchdown and an interception, Mahomes began to “pick his spots in the run game,” Mack said. His biggest run came in the fourth quarter, a 13-yard gain on third-and-go.