Kicker Jake Moody who suffered an ankle injury during the game canceled out a number of chances for the Niners to extend their lead with long field goals, but did not change the problems in the red zone. San Francisco went 1-for-6, turning red zone opportunities into touchdowns on Sunday. Missing running back Christian McCaffrey, one of the best red-zone threats in the NFL, hurts but doesn’t explain all of the Niners’ struggles to open the season.

“Same thing I said last week, not very good,” Shanahan said of his club’s red zone woes. “Before today we were in the middle of the pack and today we got even worse.”

On Sunday, the Niners were blown out in the second half, the first scoreless second half in any game Brock Purdy has started in his career.

A blocked field goal set up a touchdown, and a Nick Bosa interception turned into a chip shot field goal, creating a 23-10 lead that was never built upon again. Late, the Niners D couldn’t slow down James Conner, Kyler Murray and a surging Cardinals offense.

“It’s pretty simple. In the NFL, having turnovers and not playing complementary football costs you,” Bosa said. “Since Kyle took over, this organization has found ways to win. It’s not about how good your players are, how explosive an offense is or how good a defense is. If you turn the ball over and you don’t make plays in crucial moments on defense, you’re going to lose in the NFL. I haven’t lost any confidence in this team. It’s been a long year.”

With both the Niners and Seattle Seahawks (3-2) falling on Sunday, it sets up a short week of Thursday night battle with first place in the NFC West on the line.

“I think we need to turn the page,” Bosa said. “It’s pretty clear what happened and why we lost. I think it’s kind of a blessing in disguise that we’re playing on Thursday.”