A significant chunk of that came from a 76-yard catch and run that featured Mostert reaching a speed of nearly 23 MPH, passing Arizona Cardinals defenders in the first quarter on the way to the end zone, giving San Francisco a 10-0 lead.
It looked as though the 49ers offense was ready to run away with the game. The offense, however, wasn't able to manufacture similar explosive plays and eventually fell 24-20 to the visiting Cardinals.
Sunday was a first for Mostert. In his sixth NFL season, the running back earned his first career start. That's exactly how head coach Kyle Shanahan described it, too — "earned."
"I think Raheem just earned it last year," Shanahan said on Monday of the decision to have Mostert on the field with his teammates during the first offensive snap of the game. "The way he came on in the middle of the year, the way he finished the year, I think every running back would agree with me also that Raheem earned that.
"If you talk to Tevin (Coleman), you talk to [Jerick McKinnon] and Jeff (Wilson Jr.), I think they would agree. So, he earned it. He went out there and kept doing what he did last year.
"I thought Raheem did have a good game. We got him going on a couple of things. (He) did a good job in the pass game, too, so I was excited for him."
Nine hundred and sixty-six days after appearing in his last NFL game, Jerick McKinnon was back on the football field for his debut in red and gold. The running back signed with the team in 2018 but missed the past two seasons after suffering an ACL injury.
McKinnon finished Sunday's game with 44 all-purpose yards on three rushing attempts and three receptions. He even found his way into the end zone after hauling in a pass from quarterback Jimmy Garoppolo.
"I was real happy for Jet," Shanahan said. "I thought Jet played well, had some key plays for us. ... Jet played very well and just him being out there was an accomplishment.
"I think it had been about a thousand days since he had played. What he's gone through to get back, he's as good of a guy as there is, so everybody was pulling for him. He's worked as hard as he can, and he's also a player who's going to help us out a lot."
McKinnon was overwhelmed by emotions from the thought of finally getting back on the football field after years of rehab.
"It was really just a blessing to wake up this morning knowing I was going to get to play in a game finally," McKinnon said after the Week 1 matchup. "A lot of emotions -- I woke up, shed a couple tears, and took it all in. But God is good, and I'm back.
"It was great to be back out there with my team, playing with those guys and going to war with those guys because they've definitely been right there beside me these last two frustrating years."
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