GLENDALE, Ariz. >> The Arizona Cardinals have won five in a row, have the best record in the NFL and are 8-1 for the first time in 66 years.

All of which is overshadowed by a knee injury to quarterback Carson Palmer.

In the immediate aftermath of Palmer’s injury in the fourth quarter of Sunday’s game against the Rams, the Cardinals broke out for three touchdowns and a 31-14 victory.

But Palmer leaving on a cart was the enduring image.

“You see one of your leaders on the ground, we’re human,” Arizona’s Larry Fitzgerald said. “Long before Carson is our quarterback, he is our friend.”

Coach Bruce Arians would not speculate on the severity of the injury.

“We don’t know anything about Carson’s injury or the length, whatever it is yet,” Arizona coach Bruce Arians said. “He will be evaluated and get an MRI and everything.”

It was the same left knee that he injured Jan. 8, 2006, in a playoff game against Pittsburgh, when he tore his ACL and MCL on his first pass of the game.

The injury came two days after Palmer signed a three-year contract extension reportedly worth $50 million with $20.5 million guaranteed.

St. Louis (3-6) was leading 14-10 when Palmer was hurt.

Drew Stanton, 2-1 as a starter when Palmer was out with a shoulder injury earlier this season, came in and threw a 48-yard touchdown pass to rookie John Brown for the go-ahead score, then Austin Davis was intercepted twice by Patrick Peterson.

The second one, with Peterson tipping the ball into the air to himself, was returned 30 yards for a touchdown. Antonio Cromartie completed the fourth-quarter spree returning Davis’ fumble 14 yards for a score.

Here are some things to take from Arizona’s victory over St. Louis:

STANTON’S SUCCESS: Stanton directed the go-ahead TD as soon as he came into the game.

First, he completed an 11-yard pass, then he ran for four yards and completed a 26-yarder, setting up his big throw to Brown.

“I threw it and I honestly didn’t see it,” Stanton said. “I got dragged to the ground. Once everybody started cheering, I figured it was a touchdown and not a pick.

Stanton, who went four years without taking a regular-season snap, credited the help of Shaun Hill, now the St. Louis backup, for helping him persevere.

“Without him, I’m not here,” Stanton said. “It was kind of funny that he was here today, seeing that happen. It’s also a friendship that I was able to form that will last a lifetime.”

FITZ’S BIG DAY: Fitzgerald had another big game for Arizona, catching a season-high nine passes for 112 yards. In his last three games, Fitzgerald has 21 catches for 344 yards.

In the process, he passed Keenan McCardell into 19th place in career receptions and moved ahead of Michael Irvin into 24th place in yards receiving.

CONFIDENT SMOKEY: Brown’s diving grab for the go-ahead score was his second big late catch in three games.

He hauled in a 75-yarder from Palmer with 1:21 to play for the winning score against Philadelphia.

“That is what I am here for,” Brown said. “That is why coach Bruce Arians brought me in for, to make big plays. They say big-time players step up in big time games so I try to do the best I can when it is my time. “

DAVIS’ WOES: Davis blamed himself for the two late interceptions.

He said he underthrew his first receiver and threw too high to the second.

“I didn’t play well enough to win today,” he said. “I think the thing that I’m learning really quick is you can play really well for three and a half quarters but you’ve got to play four. You can’t have a single letdown and right now I’m having those and it’s costing our football team.”

COSTLY PENALTY: A costly penalty disputed by some of the Rams players thwarted a big St. Louis scoring threat in the third quarter.

With the Rams leading 14-10, Davis threw 41 yards to tight end Jared Cook to the Arizona 4-yard line. But Lance Kendricks was called for a blindside block on the play.

“I was just playing fast at that point,” Kendricks said. “I wasn’t trying to take him out or anything like that. I was just trying to play fast. I thought it was a clean hit.”

The Rams advanced to the Arizona 35 but one of the Cardinals’ six sacks pushed St. Louis out of field goal range.