SAN FRANCISCO -- Gone are the comfortable weeks of yore, of 2011, when Jim Harbaugh and his 49ers spent the first half of the season taking whatever they wanted and the second half anticipating the playoffs.
It's a new dawn in the NFC West, and the 49ers and an anxious crowd of 69,732 got an up-close look at it Thursday night at Candlestick Park.
San Francisco's 13-6 victory over Seattle was a brawl, rife with violent collisions, trash talking and furious coaches stalking the sidelines.
It was Harbaugh besting his old Pac-10 pal, Seahawks coach Pete Carroll.
It was Harbaugh's staff making the proper second-half adjustments to suffocate a Seattle offense led by rookie quarterback Russell Wilson, who after his team's 177-yard first half generated only 74 after halftime.
And it was the 49ers puncturing Seattle's defense for the game's only touchdown, a 12-yard pass from Alex Smith to tight end Delanie Walker that was the difference in a game of late hits, face-mask grabbing, chest-to-chest yakking -- and at least one concussion.
"They were just in the flow of the game," Harbaugh said of the extracurricular action. "It was a rough, tough football game."
Consider this a prelude to what lies ahead within the division formerly known as the NFC Worst.
"It's more smash-mouth football in this division now," linebacker NaVorro Bowman said. "Guys are determined to run the ball and not become one-dimensional."
This game was a battle for supremacy, both teams entering with 4-2 records, the same as Arizona. San Francisco now has sole possession of first place, but what once was a huge gap clearly has closed.
The NFC West is now rich with quality players, fiery coaches and quick tempers. It's a division of, above all, defense.
The Seahawks play with a savagery reminiscent of the 2011 49ers. But the 'Hawks are a different team away from home, and that was enough to provide an opening for the 49ers.
Smith was less than sharp but held together to direct the game-winning drive, using short passes and Frank Gore's explosive runs to go 86 yards on 10 plays, concluding with the scoring pass to Walker.
No play during that drive went more than 15 yards. There was no shot downfield. Even tight end Vernon Davis spent most of his time blocking, for the 49ers recognized where this game was headed.
"It was more of, 'Let's get back to our roots and do what we're good at,' " guard Alex Boone said. "That's being physical, pounding the ball."
So they rode Gore, and he responded with 131 yards, on 16 carries.
The Seahawks also ran well, often right at the Smiths, Justin and Aldon. Marshawn Lynch bashed his way to 103 yards -- the second consecutive game in which the 49ers allowed a runner to surpass the 100-yard mark.
"They run what they do really well, and they have the right man for the job in (Lynch)," Justin Smith said. "We were watching tape all week and just said, 'Man, we have to be ready to go.' "
Running the ball in the NFL is supposed to be a lost art, its death initiated by West Coast offenses spraying the ball all over the field. The Bill Walsh 49ers, you may recall, were often described as using "finesse." Well, Harbaugh is not a big fan of finesse, and it has no place in the new NFC West. These teams are built around defense and running.
That's what happens when Seattle rebuilds under a defensive-minded coach such as Carroll, and when St. Louis hires defensive-minded Jeff Fisher.
Cardinals coach Ken Whisenhunt is, like Harbaugh, an offensive mind with a defensive mentality.
The new NFC West is about beating people up. The team that beats best will win most.
That team last year was the 49ers. They found their stride a month into the season and rolled to a 13-3 regular season and into the playoffs.
It appears their NFC West competition was watching and studying.
Arizona last year finished second, at 8-8. Seattle was 7-9, and St. Louis was 2-14. The Rams, in their first year under Fisher, already have surpassed their 2011 win total. The Seahawks almost certainly will. And the Cardinals, well, we'll know more about them by mid-November.
San Francisco has 10 days to heal and prepare for the next challenger, at Arizona for a Monday night game on Oct. 29.
The 49ers realize the days of bullying this division are over. It's still theirs to win but they, too, will be bruised. There will be blood.