Quarterback Jimmy Garoppolo never has been more accurate in his six-year NFL career than in the 49ers’ memorable Week 17 victory over the Seattle Seahawks.

And one throw -- the lowest-percentage attempt all day -- stands out in particular. After all, he threw it into a hive of Seahawks jerseys.

Officially, Garoppolo completed 18 of 22 passes in the 49ers’ 26-21 victory, which clinched the NFC West championship.

But Garoppolo’s deep pass had nothing to do with the win. In fact, he fired one last throw because, well, he was so fired up that the 49ers had clinched home-field advantage throughout the NFC playoffs against the team’s biggest rival.

The normally humble Garoppolo barely could suppress his pride for connecting with an intended target in the tightest of windows. His final pass of the day ended up in good hands -- a fact he did not find out until four days later.

“That’s a good throw, then,” Garoppolo said, laughing.

Matt Pinelli, 19, of San Jose traveled to Seattle with a group of 17 that included the family of his girlfriend, Lauren Haniger. The pocket of 49ers fans were seated in the lower level, near the goal line, where Garoppolo took the final snap and plowed forward on a quarterback sneak to run out the clock.

Garoppolo had the ball in his hands as the final nine seconds ran off the clock. He figured he'd just hand the ball back to referee Tony Corrente. He waited 15 seconds after the clock ran out before acting.

“I looked for the ref initially, but no one was around me,” Garoppolo said. “So I was like ... I’m just going to throw this thing.”

As soon as Garoppolo let it fly, he turned to 49ers staff member Mike Chasanoff, who handed Garoppolo a black 49ers beanie to wear during his postgame interview on the field with Michele Tafoya of NBC Sports. Garoppolo did not follow the flight of the ball to see what happened.

Meanwhile, in Section 105, Row Y ...

“I was actually on my phone and I didn’t even know what was happening,” Pinelli said on The 49ers Insider Podcast. “I was texting my friends, saying how awesome the game was. And a bunch of Seahawks fans had their backs to field, walking up.

“I looked up from my phone to see the ball just coming towards me, like a row over. So once I saw it, I got into the aisle, and I had to push a Seahawks fan over and I jumped on the ball.”

https://www.instagram.com/p/B6t_abnJ3TK/

After securing the football, Pinelli shoved it under his shirt for safe-keeping.

Then, he began to consider the historical significance of the ball. Because the 49ers-Seahawks game was flexed into "Sunday Night Football," it was the final ball used in a regular-season game this season, this decade and in the first 100 years of the NFL.

Pinelli said he would like to get the ball autographed and framed as a keepsake from, perhaps, the most significant regular-season game in 49ers history.

Garoppolo said he “definitely” would sign the ball for Pinelli. He was just glad it ended up safely in a 49ers fan's hands.

[RELATED: Six matchups that could decide 49ers-Vikings playoff game]

“I got home and I told my mom, ‘Yeah, I threw it in the stands,’ ” Garoppolo said. “She’s like, ‘Did you hit someone?’ I said, ‘I have no idea if I hit anyone.’ ”

Now, he knows. And it gives him one last thing to remember fondly about Week 17 in Seattle.