SEATTLE — David Akers became the first kicker in NFL history to make 42 field goals in a season, and his four field goals Saturday helped push the 49ers past the Seattle Seahawks 19-17.

Akers’ 39-yard field goal with 2:57 remaining served as the winning points, and he celebrated that kick by subtly head-butting holder Andy Lee.

“All of our players and coaches are really happy for David’s success,” coach Jim Harbaugh said.

Akers missed a 52-yard field goal attempt on the 49ers’ opening series but made his next four attempts, from 53, 29, 44 and 39 yards. That 29-yard field goal in the third quarter matched the previous record of 40 field goals in a season, set in 2005 by the Arizona Cardinals’ Neil Rackers.

Jim Harbaugh is a student of football history. So does he know anything about the Decatur Staleys of 1920?

“They became the Chicago Bears,” the 49ers coach said Tuesday, confidently.

Correct. But wait. There’s more.

The 1920 Staleys also were the last team in organized major professional football history to play its first 13 games of a season without allowing a rushing touchdown. The 49ers broke the single-season record Monday night by allowing a mere field goal in their 20-3 victory over the Pittsburgh Steelers.

This means that in 14 games this season, the 49ers defense is 14-for-14 in stopping any ball carrier from scrimmage, on any team, on any field, from crossing the goal line.

Heck, the 49ers have allowed only 18 touchdowns, period — all via the pass. And the past two games, they have kept their rushing TD-less streak alive without the services of their captain, linebacker Patrick Willis. He has been a sideline spectator. He has been impressed.

“It’s been amazing to watch from over there,” said Willis, still nursing his hamstring injury but expected back for the playoffs. “The physical nature of how we play, the way we get to the point of attack … it’s crazy.”

It is also worthy of a nickname. Don’t you think? Problem is, no one has come up with a good one yet. This 49ers defense might come to be considered the franchise’s best, depending how the season concludes. But there has been no catchy moniker

attached to the unit, unlike the “Steel Curtain” of Pittsburgh in the 1970s or the “Doomsday Defense” of the Dallas Cowboys during roughly the same era.

Can’t say that I have any dynamite nicknames to offer these 49ers defenders. Unless you count the “Scarlet Smotherers” or the “Rush Rejectors,” which you definitely shouldn’t. After Monday night’s power glitches at Candlestick, I sense strong sentiment for the “Lights Out Defense.” But I personally might go for the “Nuevo Staleys.” I’m sure that 49ers offensive tackle Joe Staley would endorse it.

Harbaugh, on the other hand, would rather just keep praising the good work being done by his defenders, who are ranked No. 1 in the NFL.

“It’s outstanding,” he said, practically giddy. “It’s just awesome.”

Better than the 1920 Staleys, even? Maybe not, he conceded.

“When did the forward pass come in?” Harbaugh said. “Probably a little bit after that, right? Prior to the forward pass, it really makes it that much more remarkable.”

Actually, scholars say the first forward pass was thrown in 1905. So the Staleys did face at least a primitive air attack as they allowed just three touchdowns over the 13 games. But that doesn’t diminish what the 49ers defense of 2011 has done.

“We don’t talk about it a lot here,” Harbaugh said, “but I still feel like our guys take a lot of pride in that. It’s pretty amazing.”

That’s probably not too strong an adjective. Skeptics will note that in today’s football, most teams score the majority of their touchdowns on passes, even from inside the red zone. The implication is that we shouldn’t be so impressed by the 49ers’ rushing TD stoppage statistic.

Yet when you chart the touchdowns allowed by this season’s 49ers defense, the feat becomes more impressive. Of those 18 passing touchdowns they have allowed, just seven have come on plays that started inside the 10-yard line — only one from inside the 5-yard line.

Let me repeat that fact for emphasis.

Over the course of 14 games, only once has a 49ers opponent scored a touchdown when the line of scrimmage was at the 4-yard line or closer. And only seven times has an opponent scored when the ball has been spotted inside the 10-yard line. Otherwise, the 49ers defense has held opponents to field goals or shut them down entirely.

Was that how Harbaugh saw things happening when he and his staff began assembling their defensive strategy last summer?

“It’s a big goal to stop the run,” Harbaugh said, “but you don’t set up on your goal board at the beginning of the year to not allow a rushing touchdown for the first 14 games. You want to be good against the run. You want to stop the run. Our team has been doing that.”

With the Seattle Seahawks and running back Marshawn Lynch ahead Saturday, the streak will be in jeopardy. As will the defense’s streak of 36 consecutive games without allowing an opposing runner to gain 100 yards or more.

Nothing wrong, though, with taking a bow for what has been accomplished to this point. Credit goes to the entire defensive cast, from Justin Smith up front to pass-rushing savant Aldon Smith at linebacker and defensive backs Carlos Rogers and Dashon Goldson, who keep picking off passes. Rogers allowed himself to concede that Monday’s victory over a banged-up-but-still-strong Steelers team was a statement.

“It lets us know what we can do,” Rogers said. “But we’ve got to continue to do it.”

With a nickname or otherwise.

Contact Mark Purdy at mpurdy@mercurynews.com or 408-920-5092.

NAME THAT ‘D’
Purple People Eaters Minnesota Vikings, 1967-73, Carl Eller, Alan Page
No-Name Defense Miami Dolphins, 1972, Nick Buoniconti, Manny Fernandez
Doomsday Defense Dallas Cowboys, 1976-82, Randy White, Ed “Too Tall” Jones
Steel Curtain Pittsburgh Steelers, 1972-77, Joe Greene, L.C. Greenwood

Though darkness and light, times of struggle and moments of elevating success, the 49ers held on tight Monday night.

They did what they had to. They didn’t lose their grip through the madness.

And after the long night and longer journey, the 49ers emerged with one of their most meaningful (and memorable) triumphs in years.

Their 20-3 victory over Pittsburgh was part endurance test, part showcase, part embarrassment and part pure gut check.

There were two blackouts at Candlestick Park and multiple chances for the 49ers to flinch under fire.

Basically, it was the biggest — and definitely the darkest, literally — 49ers game in many, many years.

This was a 49ers team that had lost two of its previous three games and needed a victory to stay ahead of New Orleans for the second seed in the NFC playoffs.

This was a 49ers team that had wrapped up its playoff spot weeks ago, but badly needed a late-season emotional boost.

And they got it Monday night, on national television, against one of the best and toughest teams in the league.

The 49ers (now 11-3) even had a clear watershed moment, which came in the third quarter, after a Pittsburgh field goal narrowed the 49ers’ lead to 6-3.

The 49ers defense had played well to that point against a gimpy Ben Roethlisberger, including interceptions to end the Steelers’ first two drives.

But once again the 49ers offense couldn’t fully cash in and had to

settle for two field goals — and a 6-0 lead — going into halftime.

So the Steelers’ field goal put the onus back on Alex Smith and the offense, with only the whole sports world watching and a big percentage of Candlestick roaring for the Steelers.

Could the 49ers capitalize on this moment? Would the offense scatter like pins under pressure from the Pittsburgh defense?

Would they be able to pull this all off before another blackout struck?

Turns out, the 49ers were ready for this. More than ready.

First play of the drive: Smith fired a 31-yard pass to Vernon Davis, which dropped right over linebacker James Farrior’s coverage.

Third play: 27-yard gain on a perfectly set up screen pass to Kendall Hunter.

Fourth play: Beautiful over-the-shoulder pass and catch from Smith to Davis fading to the left side, picking up 21 yards to the Steelers’ 1-yard line.

Fifth play: Play-action roll out, lob to a wide-open Davis for the touchdown, for a 49ers 13-3 lead.

No question, the best 49ers offensive series of the season, when they needed it.

A few possessions later, early in the fourth quarter, Justin Smith recovered a Roethlisberger fumble deep in Pittsburgh territory after a swarming sack.

That led to Frank Gore’s 5-yard touchdown burst for a 20-3 lead, and that all but put the game away.

That also helped to make this more than just the night the lights went out (twice) at Candlestick.

The first blackout delayed kickoff by 20 minutes; the second blackout came early in the second quarter, and lasted another 15 minutes.

None of that seemed to bother the 49ers. None of that knocked them off stride or put them in panic mode.

After this, the 49ers have two division games to finish the regular season — a tough one on short rest in Seattle on Saturday, then at St. Louis on the final Sunday.

If they win those two, the 49ers will clinch a first-round bye and home-field advantage in the second round.

That’s a big deal, of course. And Monday night was a big deal, too.

It was a big deal all along. Everybody knew it.

But when the lights went out, then went back on, then went back out again, and the tension kept building, this game turned into 2011 touchstone.

Through everything, the 49ers just had to hold on. They did. It was not easy or always visible, but this was their test. And they aced it.

Read Tim Kawakami’s Talking Points blog at blogs.mercurynews.com/kawakami. Contact him at tkawakami@mercurynews.com or 408-920-5442.