Sierra overcame a bleak start, costly penalties and Lathrop’s punishing run game for an invigorating 39-35 win Friday at Bennie Gatto Field.

The season opener marked the first game under new head coach Jeff Abrew for the visiting Timberwolves, who are trying to reverse their fortunes following three straight one-win seasons.

“It was a hard-fought battle,” Sierra coach Jeff Abrew said “I didn’t expect anything less from Lathrop. I know they’re well coached and (Lathrop coach) Ryan (Teicheira) does a great job with those guys.

“Our guys had their moments where we weren’t looking too hot, but they stepped up in the end and showed grit. I couldn’t be happier for these guys.”

Sierra was led by junior Zak Willson, who quickly grew up in his varsity debut. He completed 11 of 17 passes for 238 yards and two touchdowns to Trevor Sutton. Sutton finished with 120 yards on four receptions, made all four of his point-after kicks and a 34-yard field goal.

Lathrop outgained the Timberwolves 395-310 in yardage but was done in by two penalties.

“For some of these seniors, this is just their third win,” Willson said. “This win feels great, especially for them. This was a great team win.”

Things did not look so promising for Willson and the T’wolves at the start. They were flagged for holding on the first play from scrimmage, and Willson was sacked on back-to-back plays by Lathrop defensive end Nathan Martinez.

Willson credited senior running back Anthony Grady for sparking the offense. The third-year starter had a quiet first half but ended with 70 rushing yards and two TDs on 15 carries as well as three catches for 29 yards.

“Grady doesn’t speak that much, but he came through as a leader,” Willson said. “He told us what we needed to do, and he’s a senior and one of our best players. I think it just clicked when he started getting on us. We meshed well together and played great.”

Sierra scored 17 unanswered points in the second quarter to take a 24-14 lead, but the Spartans went into halftime charged by Jimari Dove’s 80-yard touchdown dash.

Dove nearly went coast-to-coast again on the second-half kickoff, taking it from the 2-yard line to inside the Sierra 10. Much of that was brought back because of a holding penalty, but it did not end up hurting Lathrop as Andre Muqhar capped the drive with a 37-yard touchdown run.

Sierra had a chance to respond, but Willson’s 34-yard touchdown toss to Josh Seals was negated by an illegal substitution penalty. The Timberwolves wound up punting.

Lathrop, leading 27-24, botched an opportunity to gain separation, as Sierra safety Joseph Ramos-Fortes came up with an interception and returned it to the Spartans 15. Grady later punched in his second TD of the game.

The Spartans answered with Julio Garcia’s 2-yard run followed by his 2-point conversion that gave them their final lead at 35-31 with 7:52 remaining.

Sierra had another touchdown pass called back on the next drive — a 33-yard screen play for Grady — but made up for it two plays later when Willson hooked up with Sutton for the 18-yard, go-ahead touchdown with 3:28 to go.

The win was secured by the T’wolves when Evan Greenwood knocked Dove out of bounds on a fourth-and-5 pass play that went for no gain.

“Defensively, it was an up-and-down game, but when we needed them the most they stepped up and got the stop,” Abrew said. “Proud of the way the guys responded. They could have folded the tent several times, but they continued to make plays. Our guys just had a lot of fight in them today.”

Linebacker Brock Felt came up with the fumble recovery in the second quarter for Sierra’s other forced turnover.

While disappointed with the defeat, Lathrop has much to build on. The Wing-T attack fired on all cylinders, getting contributions from sophomore fullback Pablo Pena (11 rushes, 55 yards), Garcia (15 rushes, 85 yards, two TDs), Muqhar (seven rushes, 74 yards, two TDs) and Dove (five rushes, 102 yards).

Quarterback Teagan Shevlin was 7-of-10 for 84 yards and hit five different receivers.

“Offensively, I like where we are,” Lathrop coach Ryan Teicheira said. “Our run game was really special today. We had about six different guys carry the ball and they carried the ball well. Moving forward, that’s our bright light, is finding a rotation with the kids and fine-tuning some things. I think we’re farther ahead than in years past in Week 1, we just gave up too many big plays tonight.”

Teicheira is a former assistant coach at Sierra, where he graduated in 2001. Sierra extended its all-time lead to 9-3 in this rivalry series.