Shanahan reveals what Purdy did wrong on Cards’ game-clinching blitz

Although they had not shown any capability of finishing the job, the 49ers still had one last chance on Sunday.

But the Arizona Cardinals thwarted that opportunity, as the 49ers’ final mistake of the game sealed their fate.

The 49ers’ final error of the game was not a matter of a failure in pass protection. The Cardinals beat the 49ers with a tactical move, and quarterback Brock Purdy did not make a quick enough decision.

“They just brought more than we had to block,” coach Kyle Shanahan said after the 49ers’ 24-23 loss to the Cardinals at Levi’s Stadium.

In the instant, seven-time Super Bowl-winning quarterback Tom Brady, in his new role as an analyst on Fox, summed it up.

“Sometimes the players make the play,” Brady said. “Sometimes the scheme makes the play. And in this case, it’s a little of both.”

The Cardinals dialed up the defensive call that clinched the win with 70 seconds remaining in the game.

Purdy was a split-second slow in recognizing the pressure and dumping it off to tight end George Kittle over the middle.

“They had a blitz,” Shanahan said Monday morning on a conference call with Bay Area reporters. “When two guys blitz the back, that means you’re hot. And we just got to get rid of the ball quicker.”

The Cardinals picked an opportune time to call for an overload blitz in which they brought four pass rushers over the right side of the 49ers’ offensive line.

Right guard Dominick Puni blocked defensive tackle L.J. Collier, who lined up over him. Right tackle Colton McKitvitz was in charge of edge rusher Julian Okwara.

That left 49ers running back Jordan Mason against linebacker Krys Barnes and safety Jalen Thompson.

Mason picked up the inside rusher, Barnes, while Thompson timed it up to blast through the line and hit Purdy as he was throwing.

The pass fluttered in the air, allowing Arizona linebacker Kyzir White to make the sprawling interception to end the game.