SANTA CLARA >> Brock Purdy was just 4 years old when a banner hung outside the 49ers’ locker room reading: “Win The West.”

That was in 2005, when first-year coach Mike Nolan knew the franchise’s quickest path back to relevancy was a division title, never mind that it took until 2011 to end the Niners’ playoff drought.

Now, after Purdy’s delivered back-to-back NFC West crowns to the 49ers, they need division wins more than, well, they just need them.

The 49ers (5-4) could be recapturing the playoff form after two months of bungling the role of reigning NFC champs. Today, they can improve to 2-2 in NFC West play and move into a share of first place with the Arizona Cardinals, so long as they beat the Seattle Seahawks (4-5) at Levi’s Stadium in a seventh straight meeting.

“There’s never a moment where we walk into this game going it’s going to be given to us or anything,” Purdy said.

The 49ers’ only divisional win this season came by outlasting the Seahawks 36-24 in a Thursday night, Oct. 10 visit to Seattle. More divisional drama awaits on Thursday, Dec. 12 when the Los Angeles Rams come to Levi’s Stadium, with the regular-season finale Jan. 5 or 6 in Arizona.

Here are four keys to victory for the 49ers:

1. CMC ENCORE VS. Linebackers >> Christian McCaffrey’s most impressive play in his season debut came when he exploited a mismatch against a linebacker (Lavonte David) for a 30-yard reception via Purdy’s heroic throw in the face of pressure. The 49ers will, and always have, seek similar mismatches. The Seahawks linebacker corps has undergone a radical, in-season makeover with last month’s trade for Ernest Brown IV and Tuesday’s release of leading tackler Tyrel Dodson, who’ll be replaced by rookie Tyrice Knight.

McCaffrey winces at any thought the new-look Seahawks are easy prey and instead noted how maligned teams often pull out a surprising win under a recently named interim coach. (See: New Orleans Saints’ last Sunday).

The Seahawks’ duo of Bobby Wagner and Jordyn Brooks couldn’t stop McCaffrey last season: 259 yards and two touchdowns in the 49ers’ two wins. McCaffrey, since joining the 49ers two years ago, has run for more than 100 yards in all four of his faceoffs against the Seahawks, including a January 2023 playoff opener. Neither Achilles flared up after his 56-snap, 107-yard debut in Tampa, so “I’ll keep rolling.”

2. OVERCOME SPECIAL TEAMS >> The 49ers’ season-long issues on special teams include a Seahawks kickoff return for a touchdown. More woes came last Sunday when Jake Moody had three missed field goals (before his game-winner) and a muffed punt return caused by Darrell Luter.

Simply, the 49ers are at the point they must expect and overcome another special teams gaffe. Even tight end George Kittle noted that the desperate Seahawks could take chances such as a fake punt, on which they scored a touchdown in their 2021 game at Seattle.

“They’ve kind of had our number on big special teams plays,” Kittle said. “I’m not in special teams meetings so I don’t know what we’re doing for that but we’ve got to be on guard for everything.”

Punter Mitch Wishnowsky’s back injury prompted the 49ers to sign veteran Pat O’Donnell, who presumably will also moonlight as Moody’s new holder. Long snapper Taybor Pepper vouches for O’Donnell, having worked out with him in past offseasons in South Florida.

3. COVERING DK, ETC. >> DK Metcalf got ejected in the Seahawks’ last matchup at Levi’s Stadium, once his tackle on Fred Warner’s interception led to a scuffle also involving Deommodore Lenoir, who was ejected also with three minutes left in the 28-16 win.

In this rematch, Metcalf will return from a knee injury that cost him two games, and the 49ers’ cornerbacks will be led by Lenoir, who saunters in fresh off Wednesday’s contract extension (five years, $92 million).

This is not just Metcalf vs. Lenoir, however. Metcalf (35 receptions, 568 yards, three touchdowns) is part of a multi-prong corps that includes Jaxon Smith-Njigba (50-568-3) and Tyler Lockett (34-456-2).

Geno Smith won’t hesitate to air it out against the 49ers’ 24th-ranked third-down defense. Charvarius Ward will miss his second straight game following the death of his daughter, Amani Joi, who would have turned 2 on Sunday. Lining up with Lenoir again should be rookie upstart Renardo Green and veterans Isaac Yiadom and Rock Ya-Sin.

4. PRESSURING SMITH >> Seattle ruled out starting center Connor Williams, thus inviting the 49ers defensive front to pressure up the gut against Smith.

The 49ers need Nick Bosa to push through a hip injury like he did last game, when he endured 52 snaps with pain that was “the worst thing I’ve had to play through.” Resting rather than practicing this past week could be the tonic he needs to chase after Smith, who’s been sacked 28 times (and thrown 11 interceptions versus 10 touchdown passes). Bosa could be opposing Abraham Lucas in his season debut at right tackle. More help could come from Yetur Gross-Matos, who missed the past six games. Meanwhile, Leonard Floyd has just three sacks in nine starts, and hasn’t hit a quarterback since Patrick Mahomes on Oct. 20.

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