Green had seen the same thing from the Northwestern product when he ran with the scout squad team.
"He practices like he's playing in a game," Green said. "That's all you're going to see from him."
Jackson had eight rushes for 63 yards, including an 18-yard touchdown in the fourth quarter, the first TD of his career. He also caught a pass for 19-yard gain. Did the rookie have any nervousness playing in Heinz Field?
"He didn't bat an eye," Green said.
Selected in the seventh round of this year's draft after rushing for more than 1,000 yards in four straight seasons for the Wildcats, Jackson had to fight to make the roster after missing most of training camp with a hamstring injury.
He spent the first four weeks of the regular season on the practice squad and was signed to the active roster in Week 4.
Jackson put his time to good use, studying the playbook and waiting for his opportunity to make an impact. He got a little bit of confidence last week by running for 57 yards on seven carries in mop-up duty at the end of a 45-10 win over the Arizona Cardinals.
"When my number was called, I just had to go out there and make plays," Jackson said. "It's what we live for, being in that type of environment with the game on the line -- it's what you dream about, right?
"But you don't make it that big. You just go out there and play."
That chance happened in the second half with the Chargers sputtering on offense without an injured Melvin Gordon. The Chargers rushed for just 2 yards in the first half.
Jackson immediately made an impact.
"He has great vision," Rivers said of Jackson. "You don't lead the Big Ten in rushing or whatever he is -- all-time Big Ten rusher -- if you're [not] a heck of a player.
"He stepped up huge. Austin [Ekeler] worked hard. He made some plays for us. Then Justin gave us a little boost there and the guys were blocking the heck out of it as well. And, gosh, the cutbacks. A couple of those cuts he made and a few other ones were big."
Gordon texted Jackson and the rest of the running back group before the game to wish him well.
With the Wisconsin product out with a sprained right knee, Jackson could be relied on even more next week at home against the Cincinnati Bengals.
"He's a leader on the team and on the running back crew," Jackson said of Gordon. "He stayed in it with us, made sure we were up on all of our stuff.
"Today he wasn't able to make it, but he sent us a text this morning and have us all confidence. He has full confidence in us and he gave us confidence to go out there and play."