Steven Hauschka signals the good news — his 60-yard field goal beat the Chargers in San Diego Saturday night. / Seahawks.com

Whether the offense is under wraps or under-performing, it’s clear the Seahawks are going to have to win early games this season with scoring help from special teams and defense.

Two spectacular plays Saturday night in San Diego  — a 67-yard punt return for a touchdown by rookie Tyler Lockett and a career-best 60-yard field goal by Stephen Hauschka with 16 seconds left — took some pressure off the offensive line and allowed the Seahawks to beat the Chargers 16-15 (box score), Seattle’s first in three tries in the preseason.

But the No. 1 offensive unit has gone without a touchdown in 13 possessions, mostly due to newbies in three spots in the line. And on sweltering night in southern California, a fourth position had a newcomer. Alvin Bailey started at left tackle in place of Russell Okung, who came out of practice with a sore shoulder and was rested as a precaution.

“We’re not functioning as well as we’d like,” coach Pete Carroll said. “We’re all a little bit frustrated with it. I’m a little bit frustrated by it. But I’m not worried about it over the long haul.

“They are going to get a lot better. It just needs to hurry. We only got a couple of weeks.”

The Seahawks, with Marshawn Lynch getting his first action, had decent ground production with 117 yards on eight carries. But the pass protection was spotty and Wilson was not especially accurate, with seven completions in 15 attempts that included a red-zone drop by a wide-open TE Jimmy Graham when the ball was delivered a bit behind him on a crossing route.

Wilson also threw wild high to Graham in another red zone chance.

“I was a hair high,” Wilson said, “and he’s pretty big. That’s on me.

“We’re moving the ball now. We just have to finish. We will.”

But with one fake game left, Thursday at home against Oakland,  before opening in St. Louis against the Rams Sept. 13, Carroll’s stated urgency may go unfulfilled. Wilson was in full scurry on most of his drops, and the left side of Bailey and guard Justin Britt leaked several times, even on running plays.

But Lockett’s second-quarter return, in which he changed direction and picked up his blocking perfectly, lifted the Seahawks, just as did his 103-yard kickoff return in the exhibition opener against Denver.

“We shouldn’t be surprised — he’s done this his whole life,” Carroll said. “It was an incredible run.

“We won’t always get a touchdown, but it will always be a great threat . . . special teams have been a great factor for us throughout the preseason.”

That point was underscored when Hauschka stunned the remainder of the crowd with his game-winner that barely slipped over the crossbar just minutes after he’d missed a 58-yarder by about a foot.

“It’s good to get out there and just swing away,” Hauschka told KIRO-TV. “I love any change to get a long one. I hit the 60 a little cleaner than the 58. And it was into the wind.”

Hauschka hit from 40 with 51 seconds left in the second quarter to give the Seahawks a 10-6 halftime head. In the third quarter, with Wilson and most of the first unit still in the game, the Seahawks went for 71 yards and 14 plays before another red-zone sputter. Hauschka delivered from 27 yards for a 13-6 lead.

The Chargers drew back in the game against Seattle’s second-unit defenders when RB  Brandon Oliver took a short pass in the flat and went 70 yards for a touchdown. The Chargers went for the lead with a two-point conversion attempt but LB Brock Coyle made the tackle that preserved the advantage.

The Chargers took the lead with 4:16 left on Nick Novak’s 52-yard field goal. But Seattle’s reserve defenders stopped the Chargers reserve offense twice in the final minutes to give Hauschka his range-finder chance before hitting the target.

The defense appears ready for the season, with FS Dion Bailey doing a credible job standing in for holdout Kam Chancellor. He was in on 10 tackles and helped keep Chargers star QB Philip Rivers from getting his team into the end zone in the first half.

New defensive coordinator Kris Richard called for more blitzes than the usual conservative Seattle standard, and most seemed effective. Carroll said he was pleased with the results.

“This looks to be a team, maybe more than others, that we can bring pressure,” he said.

The offense is another story. Lockett has half of Seattle’s four preseason touchdowns, the other two belong to LB Bobby Wagner on a pick six and backup QB R.J. Archer on a late pass against Denver.

“Russ missed a couple tonight,” Carroll said. “Just wasn’t as good as it needs to be.’’