ST. LOUIS (AP) -- Jared Cook's first trip to the end zone was a disaster. He ended up on his backside minus the ball and wondering what happened.
Sam Bradford urged the gifted tight end to forget about the missed opportunity, and the key offseason acquisition for the St. Louis Rams certainly made amends.
Cook caught two touchdown passes from Bradford and had a key 25-yard reception that led to Greg Zuerlein's tiebreaking field goal with 40 seconds to go, helping St. Louis rally for a 27-24 victory over the Arizona Cardinals on Sunday.
It was an impressive turnaround for the 26-year-old Cook after he fumbled away a potential touchdown in the first quarter.
''I told him when we came back to the sideline, I said, 'Hey bro, be ready. It's coming right back to you,''' Bradford said.
''It would have been easy for him to get down out there. He showed a ton of maturity and confidence.''
Zuerlein, one of the Rams' top rookie finds last year, made all four of his field-goal attempts, including a 38-yarder that tied it earlier in the fourth. He made seven field goals from 50 yards or longer last season and had distance to spare on the key kick.
''Basically, I stay calm, swing like I know how and the rest takes care of itself,'' Zuerlein said. ''There's no better feeling.
''I don't even know the distances when I go out there to be honest, I just go out there and try to do my job.''
The kick produced the Rams' first season-opening victory since 2006.
''It's a great way to start the season, of course,'' said Robert Quinn, who had three sacks and two forced fumbles.
Arizona got a defensive touchdown, and Larry Fitzgerald caught two TD passes from new quarterback Carson Palmer. But coach Bruce Arians was unable to get his first victory with his new team.
Palmer was 26 for 40 for 327 yards and an interception and Fitzgerald had eight receptions for 80 yards, but none in the fourth quarter.
''We felt like we gave this game away,'' Fitzgerald said. ''In the second half it felt like the drives weren't as sustained and we have to improve on that.''
The Cardinals had an 11-point lead after Fitzgerald's 24-yarder late in the third quarter. Defensive tackle Dan Williams had a 2-yard interception return off a tipped ball.
Arizona outgained St. Louis 390-366 in total yards but mustered just 67 yards and four first downs in the fourth quarter.
''Obviously, late in the ballgame we've got to make plays on third down, then keep drives alive to win the game,'' Arians said.
Cook had seven catches for 141 yards and the first multi-touchdown game of his career, with one big blemish.
He fumbled away a potential 55-yarder that would have opened the scoring when rookie Tyrann Mathieu punched the ball free at the 8 and the play resulted in a touchback.
''It took us a while to get it going,'' Cook said. ''It was a good day overall.''
Mathieu arrived with a big-play reputation as a third-round pick out of LSU, where in two seasons he forced 11 fumbles and recovered eight fumbles with two touchdowns.
Williams scored on his first career interception after Matt Shaughnessy deflected Bradford's pass from the 4.
Bradford was 27 for 38 for 299 yards for the Rams, who leaned on Zuerlein's leg after twice settling for field goals off takeaways deep in Arizona territory.
Zuerlein's 38-yarder tied it at 24 with about nine minutes to go. Quinn set up the field goal when he burned Cardinals left tackle Levi Brown for a sack and forced a fumble that was recovered by Chris Long.
''Other than the three sacks, I had a pretty good day,'' Brown said.
The Rams lost yards after Trumaine Johnson's 29-yard interception return to the 4 in the first half.
Cook began atoning with a 13-yard catch that tied it at 10 with 26 seconds to go in the half, stretching the ball across the pylon while getting shoved out of bounds by Yeremiah Bell. Cook found an open spot in the back of the end zone on a 1-yard catch in the fourth off a nice play-action fake by running back Daryl Richardson, who leaped over the line.
The Cardinals opened the scoring in the second quarter on Fitzgerald's 4-yard catch on a perfectly thrown fade in the left corner of the end zone to beat Janoris Jenkins.
NOTES: Neither team had major injuries to report. Rams OT Rodger Saffold missed time in the second quarter with a left knee injury but returned before halftime. ... Saffold and LT Jake Long both had penalties on St. Louis' opening possession but Bradford did not get sacked. ... Arizona's Andre Roberts also had eight catches for 97 yards. ... The Rams totaled 67 yards rushing on 24 carries, with Richardson getting almost all the work on 20 carries for 63 yards.
AP NFL website: www.pro32.ap.org