GLENDALE, Ariz. — Bruce Arians watched Todd Gurley's second-half coming-out party and proclaimed him "a heck of a back."
And a backbreaker for Arians' Cardinals.
The St. Louis rookie rushed for all but two of his 146 yards after halftime and the Rams held on to hand Arizona its first loss of the season, 24-22 on Sunday.
Gurley saw his most extensive action as a pro, and his 52-yard run set up the winning touchdown.
"It is just football," he said, shrugging off the performance. "I have played it my whole life, and you ready your keys and study the game and everything will slow down for you."
Nick Foles threw for three touchdowns, two after Arizona turnovers, and St. Louis' defense held the Cardinals to field goals on four of five trips inside the red zone to help lead to the upset.
Arizona had a third-and-2 play at the Rams 43 in the final minutes, but Carson Palmer overthrew receivers on consecutive plays to turn the ball over on downs in the NFC West game.
"You're not going to win many games kicking field goals in the red zone and losing the turnover battle," Arians said, "especially in our division."
St. Louis scored after Arizona rookie David Johnson fumbled away the opening kickoff, the first time the Cardinals have trailed this season, and never relinquished the lead. Johnson also dropped a touchdown pass but had some big plays late.
The bad outweighed the good, Arians said. "He played like a rookie today," the coach added.
After scoring 48 and 47 in its previous two games, Arizona got five field goals from Chandler Catanzaro — from 21, 27, 42, 38 and 29 yards.
Gurley, who was delayed in his pro debut by a knee injury, gained 9 yards in six carries in his debut last week against Pittsburgh and had 5 yards on three attempts in the first half Sunday.
"Last week was tough on him," said Rams receiver Tavon Austin, who had two touchdown catches. "He came out this week and exploded."
With the Rams ahead 17-15, Gurley burst through the line and broke a couple of tackles for a 52-yard gain to the Arizona 16, and Foles threw 12 yards to Austin and the lead was 24-15 with 8:16 to play.