Arch Manning, Louisiana high school football legend, breaks off ...

Arch Manning is reinforcing his case for college football's best backup quarterback.

Manning, the Texas redshirt freshman and Louisiana high school football great, broke off a 67-yard touchdown run on a quarterback keeper in the first half of a 56-7 home win against UTSA on Saturday.

Manning ended up having a career day after starter Quinn Ewers exited the game in the first half. He completed 9 of 12 passes for 223 passing yards and four touchdowns along with 53 yards rushing and a score.

With the run, the nephew of Peyton and Eli Manning produced the longest touchdown run from a Texas Longhorn since Vince Young in 2005.

Texas is ranked No. 2 in the country in the Associated Press poll.

Manning is playing his first meaningful season in college after establishing himself as the nation's top high school prospect, let alone quarterback.

He led Isadore Newman (Lousiana) to a 34-9 record while tossing 8,599 yards and 115 touchdowns with 20 interceptions.

In Week 1, he completed 5 of 6 pass attempts for 95 yards and two touchdowns in a 52-0 win over Colorado.

Before the Longhorns beat Michigan at the Big House in Week 2, Manning went to an Austin High School football game as a spectator.

Manning entered the season the backup toformer Southlake Carroll standout Quinn Ewers.

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-- Andy Buhler | andy@scorebooklive.com | @sblivetx