Game review

OFFENSE

That was a disjointed mess. And much of it wasn’t the fault of the 21-year-old rookie QB making his first NFL start — three drops, five holding penalties, all in the second half, and failures on fourth-down situations in which 2, 1, 1 and 4 yards were needed. They drove the ball decently and produced 19 first downs, 338 yards, had possession for nearly 32 minutes and averaged 5.7 yards per play. But they produced only 10 points because they rarely came through when it mattered most, going 4 of 16 on third- and fourth-down conversions. The kid QB? He looked OK considering his inexperience, but Kyle Shanahan clearly doesn’t believe he’s ready to run anything approximating the 49ers’ offense at this stage.

DEFENSE

Can a defense take a bow after a loss? Perhaps not, but that was a winning performance against an offense that arrived averaging an NFL-best 35 points a game. Arizona scored 10 points in the first 54 minutes and had season lows in first downs (20), yards (304) and yards per play (5.1) and converted just 3 of 10 third downs. For the second straight game against the Cardinals, the first being their December win, the 49ers made Kyler Murray look meh, at least by his standards. Murray (7 carries, 1 yard) rarely looked to run, partly because the 49ers were disciplined with their pass rush and were able to hem him in the pocket. Cornerback Dontae Johnson’s forced fumble could have been a game-winning play.

SPECIAL TEAMS

Punter Mitch Wishnowsky was rarely used — that’s what happens when you have five fourth-down conversion tries — but he had a 58yard boot and a strong net average (42.5 yards) on his two kicks. Fill-in kicker Joey Slye, also lightly used, was flawless: He drilled a lategame 47-yard field goal and made his extra-point attempt, and each of his three kickoffs resulted in touchbacks. The 49ers stuck with Trenton Cannon as their kickoff returner, a surprise considering his travails the previous week. Cannon wasn’t tested as all four Arizona kickoffs were touchbacks.

COACHING

Trey Lance is a 6foot-4, 224-pounder whose best asset at this point of his career is his legs. So why not try a QB draw on 4th-and-2 from Arizona’s 34-yard line in the first quarter when you have a new kicker? It didn’t work, but you can see the logic. However, the 49ers were trailing 10-7 midway through the fourth quarter and the Cardinals’ first four second-half drives had produced three punts and a turnover. But Shanahan decided to go for it on 4th-and-4 from Arizona’s 48, a situation in which Lance would have to get it done with his arm. The pass was batted down. Five plays later, the Cardinals scored a TD that required them to cover just 52 yards. Game over.

OVERALL K