Mostert was just shy of speeding in a school zone on TD sprint

49ers' Raheem Mostert

If you blinked, you might've missed Raheem Mostert scoring the 49ers' first touchdown of the season on Sunday against the Arizona Cardinals.

At one point, he was just shy of California's speed limit within a school zone.

The running back clocked a top speed of 22.73 mph during his 76-yard reception, which Next Gen Stats pegged as the league's fastest by a ball carrier over the last three seasons.

Mostert took the throne from former 49ers teammate Matt Breida, who hit 22.3 mph on an 83-yard touchdown run against the Cleveland Browns last season.

Not bad for your first career NFL start.

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Yes, Mostert, who seized the reins as the 49ers' top running back down the stretch last season, had never started a game prior to Sunday's season opener at Levi's Stadium. The 28-year-old picked up right where he left off in Week 1 against the Cardinals, ending the first half with 109 all-purpose yards on 11 touches and the aforementioned TD.

The second half of his first start will be a difficult act to follow.