The Justin-Siena football team’s opponent Friday night looked as hungry as Braves coach Rich Cotruvo had predicted — for the first five minutes, anyway.

Tamalpais, after nearly scoring its first points of the season in the first quarter, gave up one big play after another as Justin-Siena rolled to a 40-0 Marin County Athletic League rout at Braves Field.

Justin-Siena (3-0 MCAL, 5-0 overall) stopped the Hawks (0-3 MCAL, 0-5 overall) on fourth down at their own 27-yard line to open the game, but had sputtered itself on offense.

After Braves quarterback Kevin Reinell recovered his own fumbled handoff on second down, he threw his 10th interception of the season. Hawks standout Pat Wall returned it to the Braves’ 49.

Four plays later, Wall caught an 11-yard pass from backup quarterback Nick Wagner for a first down at the Justin-Siena 14.

But the Braves recovered a fumble at the 11 on the next play and drove all the way the other direction in 10 plays, scoring on a 31-yard run by David Ichikawa (10 carries, 110 yards).

“Young teams (like ours) have to feel opponents out,” Justin-Siena head coach Rich Cotruvo said. “Once we realized, ‘Hey, we can do this,’ we got it going, but we have to work on (limiting mistakes).”

Reinell (7-of-8 passing, 149 yards, two TDs) appeared to get his confidence back just before the first touchdown by eluding a pass rush and releasing a 15-yard pass to Chris Meyer to the Tamalpais 31.

“We came out playing flat because we knew we were the better team,” the sophomore said. “I tried to relax more because it helps me make better decisions and not force the ball into coverage.”

The first of two sacks by Anthony Principe forced the Hawks into a three-and-out on their next series. Garrett Wright returned the punt 55 yards for another Braves touchdown on the last play of the first stanza, breaking two tackles along the way. Adam Eberwein followed with another extra point for a 14-0 lead.

With Tamalpais forced to the air, Jake Kerr sacked Wagner on the next two plays to help force a punt that Wagner booted impressively to the Braves’ 15. But Reinell took any momentum that might have generated by finding a wide-open Meyer (two catches, 100 yards) for an 85-yard touchdown pass. Eberwein’s extra point was blocked, but Justin-Siena had a commanding 20-0 lead.

After sacks by James Thompson and Eric Datangel forced another three-and-out, a clipping penalty on Wright’s punt return got the Braves started at midfield. But shortly after, Alex Sanchez made a falling catch at the 4 and Reinell found Ichikawa for a scoring pass and 26-0 lead with 4:46 left in the half.

Justin-Siena appeared it would extend the lead when the Hawks gave up the ball at their own 37 on another fake punt. But four plays later, the Braves coughed up a fumble at the Tamalpais 6.

Despite its comfortable lead, Justin-Siena didn’t turn the ball over after halftime. Its two turnovers on the night was half its season average.

“We played nearly error-free football in the second half,” Cotruvo said. “There were a lot of positives tonight.”

The Braves didn’t attempt any passes in the second half. They made it 33-0 with a 10-play, 72-yard drive sparked by Ichikawa’s 23-yard gain and capped by Stephen Shafer’s 4-yard TD run. Sacks by Eberwein and Principe set up an 11-play, 50-yard scoring march iced by Shafer’s 3-yard plunge.

In next Friday’s Homecoming game, the Braves will host a Redwood squad (3-1 MCAL, 3-2 overall) that rolled 35-0 over San Rafael on Friday — a team Justin-Siena edged just 22-19.

“From here on out, every team will be good,” Cotruvo said.

“In this game, we wanted to make a statement and put up a lot of points,” Reinell added. “But we’ll need to be more focused in every game the rest of the year.”