SANTA CLARA >> Sandwiched between their home opener 11 days ago and next Sunday night’s visit by the Dallas Cowboys is … a trap game for the 49ers?

No, that can’t be right. The schedule says today’s game is against the Arizona Cardinals.

Any NFC West matchup carries extra weight, and the undefeated Niners (3-0) insist they aren’t taking lightly the incoming Cardinals (1-2). Nor should they.

“They’re a team that really should be 3-0 right now,” 49ers coach Kyle Shanahan said.

The Cardinals have taken a fourth-quarter lead into each of their games, only to lose against the Washington Commanders and the New York Giants. Last Sunday, they held the lead for a 28-16 upset of Dallas, a 12 1/2-point favorite.

“Arizona looked like a really solid team that was playing harder than Dallas,” said defensive end Nick Bosa.

Incidentally, Shanahan has lost more times at home to the Cardinals than any other NFC West visitor, with the 49ers winning only 2-of-6 meetings at Levi’s Stadium (in 2019 and last season).

Here are the 49ers’ keys to winning this one:

1. SAFE-AND-SANE QUARTERBACKS

Neither Brock Purdy nor Cardinals counterpart Joshua Dobbs have had a pass intercepted this season. Purdy’s streak of 190 passes goes back to last season. Since being picked off against the Raiders on New Year’s Day, Purdy has posted a 110.5 passer rating (125-of-190, 1,644 yards, 10 touchdowns, no interceptions).

“I pride myself in not harming our team,” Purdy said. “It just comes down to trying to be selfless, making the right decisions, being prepared for scenarios, giving our guys on offense a shot to catch the ball, and being smart for our defense and not putting them in a bad situation.

“Definitely, it’s on my mind every single play, every snap, being smart with the ball.”

Purdy has won all but one game since replacing Jimmy Garoppolo on Dec. 4 against Miami, the exception being the NFC Championship Game against Philadephia in which he tore the ligament in his right elbow.

One area of needed improvement: communication on the snap count with center Jake Brendel. Purdy took the blame for gaffes that resulted in two botched snaps early in the second half of the past two games. Purdy’s only turnover this season came on a strip-sack fumble in the Sept. 10 rout at Pittsburgh.

Dobbs will try to become the sixth Cardinals starting quarterback to win at Levi’s Stadium in 10 visits, a procession featuring Drew Stanton (two wins), Kyler Murray, Colt McCoy, Carson Palmer and Josh Rosen. Dobbs has lost two fumbles, and had none of his 82 passes intercepted (while completing 72 percent for two touchdowns and just 183 yards per game).

2. EAGLES FLASHBACK?

The 49ers don’t see NFC Championship Game ghosts when watching film of the Cardinals. But they’ll admit resemblances do exist defensively, as expected, because Cardinals’ first-year coach Jonathan Gannon previously served as the Eagles’ defensive coordinator.

“There are some similar things for sure within the scheme that we had game planned for last year in the playoffs and whatnot,” Purdy said, “but at the same time, man, it’s like they’ve got different players and just their style is a little bit different compared to Philly.”

A refresher (though some 49ers fans may want to skip to the next paragraph): The 49ers were down 7-0 when Purdy entered the NFC title game and took them to midfield within five snaps. Then came play No. 6, and Hasson Reddick wrecked Purdy’s elbow to set in motion the 31-7 rout.

“Yeah, there are some similarities, some differences. They do a lot of things well,” Christian McCaffrey said of the Cardinals. “Their defense plays really hard. They have a lot of talent. They’re scrappy.”

Arizona is led by linebacker Khyzir White, who is the first Cardinal in 40 years with 30 tackles, a sack and an interception through three games. White had 14 tackles and an endzone interception with three minutes left in the victory over Dallas.

3. REV UP RUN DEFENSE

With the 49ers offense scoring 30 points per game, opponents have tried to play catch-up through the air. Thus, the 49ers defense has faced a league-low 43 runs (159 yards, 3.7 per carry; two touchdowns).

“It’s been good so far, but I don’t think we’ve been challenged a ton,” Shanahan said, referring specifically to the 49ers’ run defense. “Our biggest challenge will be this week, and going ahead, it will only get stronger.”