INGLEWOOD, Calif. -- It was after the coin toss, a few minutes before the opening kickoff, when Anthony Lynn was hit with the news he could not possibly anticipate.

Tyrod Taylor, the Los Angeles Chargers' starting quarterback, was experiencing chest pain that necessitated a trip to the hospital, meaning Justin Herbert, the 22-year-old who was drafted sixth overall only five months earlier, would be pressed into action against the defending Super Bowl champions.

It took Lynn about 30 seconds just to process the information.

Then he found Herbert.

"I think he thought I was joking," Lynn, the Chargers' fourth-year coach, said. "I had to tell him a couple times, 'No, seriously, you're the starting quarterback.' Once he realized he was the guy, he was fine."

Herbert -- possibly helped by having no time to think about the most important game of his life -- impressed in his surprising NFL debut, throwing for 311 yards and accounting for two touchdowns in his team's first game at SoFi Stadium. But he could only watch, with his helmet off and his hands on his hips, as Kansas City Chiefs kicker Harrison Butker delivered an improbable 58-yard field goal to hand the Chargers a crushing 23-20 loss in overtime on Sunday.

Lynn said he was impressed by Herbert -- but apparently not enough to consider a change at quarterback just yet.

"I'm gonna wait and see what type of health Tyrod is in," Lynn said. "He was our starter for a reason, and if he's 100 percent, ready to go, he's our starter. But I know that Justin can pick up the slack if he can't."

Herbert joined Andrew Luck (2012) and Cam Newton (2011) as the only top-10 quarterbacks to throw for more than 300 yards in their first start and still lose since 2001. And he joined a man named Bobby Clatterbuck (1954) as the only players to accumulate a rushing touchdown and a passing touchdown in the first half of their NFL debuts. At one point, Herbert led a 10-minute, 21-second drive that stood as the Chargers' longest in four years. And before that, in the game's first possession, he scored on a 4-yard scramble, snapping a Chargers streak of 137 consecutive regular-season games without a rushing touchdown from their quarterback.

But it was one mistake and one missed opportunity that spoiled Herbert's debut.

The mistake came in the final seconds of the third quarter, when Herbert scrambled to his left, ignored several yards of open space in front of him and instead threw deep to wide receiver Keenan Allen, across his body and into double coverage, getting picked off by Chiefs cornerback L'Jarius Sneed.

"It would've been great had I just took off and run and got what I could have," Herbert said. "Unfortunately, I threw it and it was a big turnover, and we can't turn the ball over to a team like that and expect to get away with it."

The Chiefs proceeded to tie the game on a miraculous 54-yard connection between Mahomes and Tyreek Hill on which Mahomes unleashed a pinpoint deep ball while rolling right and throwing off one foot. But Herbert came back to lead the Chargers up the field, then faked a pitch and picked up 11 yards on the ground to make it first-and-goal from the Chiefs' 4-yard line -- setting up the missed opportunity.

The Chargers failed in their three consecutive chances near the goal line, a result, Lynn said, of Herbert not getting as many red zone opportunities in practice because he wasn't running with the first time. The field goal made it a lot easier for the Chiefs to drive the ball up field and tie the game as time expired, prompting an overtime period that began with a Chargers three-and-out and ended with Butker's field goal -- the second longest made in overtime since regular-season overtime began in 1974.

"It's adversity," Herbert said of the loss, which extended the Chiefs' winning streak to 11 games dating back to last season and left the Chargers 1-1 to begin 2020. "I know we'll learn from it. In the long run, it's gonna help us."

Herbert had some misses, particularly when he saw wide receiver Mike Williams late over the top and gave Chiefs safety Tyrann Mathieu enough time to make up ground and bat the football away in the end zone. But he also made some impressive throws, most notably a 25-yard third-down strike to Allen that was perfectly placed between two defenders.

"It sucks what happened to Tyrod; I can't believe that," Chargers defensive end Joey Bosa said. "I've never heard of anything like that before in my life. But it was great to see Herbie out there. I've been liking what I've been seeing from him. I think he's gonna be a good player, and I think he showed out today. Obviously, he made some mistakes with the pick, but we all made mistakes. And for it being his first game, I thought he showed a lot of great stuff."