GLENDALE, ARIZ. — Arizona overcame an interception, a missed field goal and the loss of starting quarterback Carson Palmer to injury in the fourth quarter and the Cardinals beat the St. Louis Rams 31-14 for their best start in 66 years.

The Cardinals lead the NFC with a record of 8-1. The last time the franchise started a season 8-1 was 1948 as the Chicago Cardinals.

Arizona has won 15 of its last 18 games under coach Bruce Arians, whose team is 5-0 at home and in complete control of the NFC West. The Rams fell to 3-6.

It didn’t look good for the Cardinals early in the fourth quarter.

Palmer was harassed by safety Mark Barron, who grabbed the quarterback’s jersey just enough for Palmer to buckle under his own weight.

He had to be helped off the field and was done for the day. Early reports indicated the Cardinals fear Palmer tore the ACL in his left knee, the same injury that led to reconstructive surgery for Palmer in 2006 with the Cincinnati Bengals.

Rookie kicker Chandler Catanzaro, who had been a perfect 17 of 17 on field-goal attempts, missed a 53-yarder with the Cardinals trailing 14-10.

In stepped backup Drew Stanton, who was forced to start three games earlier in the season when Palmer was out with a nerve issue in his right shoulder. Stanton completed his first two passes, then went deep down the middle and connected with rookie receiver John Brown for a 48-yard touchdown.

It was Brown’s fifth touchdown reception, all of which have come at University of Phoenix Stadium.

After that, the Cardinals’ defense led the way, as cornerback Patrick Peterson returned his second interception in as many possessions 30 yards for a touchdown. Fellow cornerback Antonio Cromartie returned a fumble by quarterback Austin Davis 14 yards for another score.

The Cardinals forced three turnovers in the fourth quarter, a portion of the game they’ve owned all season. They’ve now outscored their opponents 91-34 in the fourth quarter. Only the Chiefs have allowed fewer fourth-quarter points (28).

With the three forced turnovers, the Cardinals are now tied with the Patriots for the best turnover ratio (plus-12) in the NFL. Of their 19 total takeaways, an NFL-high 12 have come in the fourth quarter.

The Cardinals sacked Davis six times and they entered the game with a total of just eight, tied for the second-fewest in the league.

Davis ended the game 17 of 30 for 216 yards and one touchdown. Before he left the game, Palmer was 25 of 36 for 241 yards with no touchdowns and one interception.

Stanton was 3 of 5 for 85 yards and a touchdown.

The momentum started to shift late in the third quarter with the Cardinals mounting a drive behind six Palmer completions. He had gotten them down to the Rams’ 15-yard line when on third and 11, he tried to lead rookie running back Marion Grice with a pass across the middle.

Grice, getting his first serious action of the season, seemed to stop running his route and Rams linebacker Alec Olgetree was only more than happy to step in and intercept the pass. He returned it 43 yards.

St. Louis couldn’t convert the turnover into any points, however, and defensive end Calais Campbell’s second sack of the game forced the Rams to punt.

The Rams went into halftime holding a 14-10 lead thanks to a 59-yard touchdown pass from Davis to tight end Jared Cook with 1 minute, 50 seconds remaining in the second quarter.

Cook got the inside track on rookie safety Deon Bucannon and roared downfield, hauling in a perfectly thrown ball from Davis and keeping his feet inbounds just before crossing the goal line.

St. Louis scored first, driving 62 yards on its third possession of the game with Benny Cunningham capping the honors with a 3-yard run.

The Cardinals answered right back. Palmer completed five passes to four different receivers and Andre Ellington ran a little toss sweep for a 3-yard touchdown of his own.

Catanzaro gave the Cardinals a 10-7 lead with a 43-yard field goal after a 36-yard, 11-play drive stalled at the Rams’ 25.

Wide receiver Larry Fitzgerald led the Cardinals with nine reception for 112 yards.

NOTES: With his 15-yard catch early in the second quarter, Cardinals WR Larry Fitzgerald increased his career receiving yardage to 11,905 to move past Hall of Famer Michael Irvin (11,904) and into 23rd place on the NFL’s all-time list. … After missing the past two games with a knee injury, Rams CB Janoris Jenkins was back in the starting lineup and was matched mostly against Fitzgerald. … St. Louis rookie FS Lamarcus Joyner suffered a groin injury in the second quarter and did not return. His status wasn’t immediately known. … Cardinals rookie DE Ed Stinson wasn’t expected to play after suffering a groin injury at the end of Friday’s practice, but he was in Arizona’s regular rotation among along the defensive line.