By Doug Haller, Matt Barrows, Vic Tafur and Sam Jane

Mac Jones had a solid stint as the San Francisco 49ers’ fill-in quarterback, impressing fans and coach Kyle Shanahan with his accuracy and command of the offense while going 5-3 as a starter. But Brock Purdy answered any lingering doubts about who the team’s starter is with a strong return from his toe injury Sunday.

Purdy completed 19-of-26 passes for 200 yards and three touchdowns against the Arizona Cardinals at State Farm Stadium. While his numbers were modest, Purdy moved the offense with ease, completing strikes to six different receivers. Purdy recaptured his connection with tight end George Kittle, who advocated for the quarterback this week.

It was a confusing day for the Cardinals’ offense. Jacoby Brissett completed an NFL-record 47 passes with just 10 incompletions, extending his strong play as a starter. He threw for 452 yards, as Arizona’s rushing attack managed only 2.6 yards per carry. Despite Brissett’s record, the Cardinals’ offense struggled elsewhere. Arizona turned it over three times, committed 17 penalties for 130 yards, including a touchdown-wiping holding call, and rushed for just 36 yards.

San Francisco’s remaining schedule features only two teams with a losing record, as it will take on the Carolina Panthers, Indianapolis Colts, Chicago Bears and the Seattle Seahawks. With the Los Angeles Rams and Seahawks facing off, Sunday was a good step for the 49ers to maintain pace atop the NFC West.

Purdy’s big day

Purdy wasted no time announcing his return, dropping in a perfect 30-yard touchdown pass to Kittle on the team’s second possession. He finished with three touchdown passes —  two to Kittle — as the 49ers cruised to victory in his first start back after he missed six games with a turf toe injury.

The running game never got going, but the 49ers didn’t really need it as the Cardinals were flagged for 17 penalties. Purdy let it rip on a couple of dangerous passes into traffic, but finished  with a tidy line of 19-for-26 for 200 yards and no interceptions.

Kittle, while praising backup Mac Jones’ success this season, was very excited about Purdy’s return because of the QB’s mastery of Shanahan’s system — and he celebrated with six catches for 67 yards and the two scores. — Vic Tafur, 49ers beat writer

Big day for San Francisco’s special teams

Skyy Moore opened the game with a 98-yard kickoff return, heralding an eventful day for both teams’ special teams units. The 49ers’ kickoff return unit, moribund in recent seasons, has sprung to life in recent weeks. In addition to Moore’s big return, Brian Robinson Jr. had a 42-yard return in the second quarter. Eddy Pineiro missed two extra points in the first half – he’s missed four on the season – and came away from a successful third-quarter extra point clutching at the back of his right (kicking) leg.

Punter Thomas Morstead handled the ensuing kickoff. Pineiro also appeared to have his first field-goal miss in a 49ers uniform when 6-foot-8 Calais Campbell blocked his 62-yard attempt at the end of the first half. Campbell, however, made contact with long snapper Jon Weeks, drawing a 15-yard penalty. Pineiro’s redo from 47 yards was good, as was a 47-yarder early in the third quarter.

That makes Pineiro 22-of-22 since joining the 49ers in Week 2. It was a tough day for tall field-goal defenders. Alfred Collins, the 49ers’ 6-6 rookie defensive tackle, got a hand on a Chad Ryland attempt from 26 yards in the second quarter, but it still managed to pass over the crossbar. — Matt Barrows, 49ers beat writer

Cardinals’ season quickly spiraling

I didn’t think the Cardinals could play worse than they did last week in Seattle, where they fell behind 35-0 in the second quarter. I was wrong.

They showed little interest or pride in Sunday’s home loss to San Francisco. The tone was set on the opening kickoff after Moore returned it 98 yards, setting up an easy touchdown. It got worse from there.

The Cardinals committed 17 penalties for 130 yards. The penalties were the most for the organization since at least 1936. In addition, Brissett, who set an NFL regular-season record with 47 completions and threw for 452 yards, threw two interceptions.

Tight end Elijah Higgins lost a fumble near the goal line. Arizona totaled 488 yards and never had a chance. Arizona was short-handed, playing without several key players, including top receiver Marvin Harrison Jr., who was out with appendicitis. But injury issues don’t make the Cardinals unique, it just gives them an excuse.

The Cardinals have a lot to figure out. The future of injured quarterback Kyler Murray will hang over the organization for the rest of the season and probably beyond. The offensive line needs upgrades. The last thing the front office needs is a head-coaching change.

In his third season, coach Jonathan Gannon has been considered safe throughout this season’s struggles, but the Cardinals are piling bad efforts. And that’s never a good thing. — Doug Haller, Cardinals beat writer 

Turnovers galore for the Cardinals

The 49ers came into Sunday’s game second to last in the NFL in interceptions with one, but doubled that number against the Cardinals. Safety Malik Mustapha hauled in a deep pass for the first one, and then Deommodore Lenoir made up for getting beat deep a few plays earlier with an interception and 64-yard return. Lenoir had been questionable with a calf injury.

Rookie cornerback Upton Stout also had a forced fumble at the goal line, as the secondary bounced back from an ugly loss to the Rams. — Tafur

Injuries continues to plague 49ers

Though the 49ers’ injury bug seemed to buzz off in Week 10, it was back in full force. Pineiro, the team’s points leader this season, never returned to the game after his third-quarter hamstring injury.

Defensive end Robert Beal Jr. suffered a concussion while linebacker Tatum Bethune left the game early with an ankle injury. Bethune has been playing middle linebacker – and calling the defensive plays – since Fred Warner broke his ankle in Week 6. His absence was underscored when his replacement, Curtis Robinson, briefly went to the sideline in the third quarter, which sent Luke Gifford into the game at middle linebacker.

Though Robinson returned to the field, the 49ers may have to find another inside linebacker if Bethune is out Week 12 against the Carolina Panthers. One option is practice squad linebacker Jalen Graham, who’s lined up at middle linebacker in previous training. — Barrows