Cornerback Patrick Peterson celebrates his interception return for a touchdown during Sunday's 31-14 win over the Rams.

The Rams held the lead for most of the game on Sunday, which meant their offense could afford to minimize risks and play it safe.

When John Brown caught a 48-yard touchdown pass with 7:40 remaining to put the Cardinals ahead by three, that all changed.

"It was that feasting time," coach Bruce Arians said.

The defense played pretty well for most of the contest but pushed it into overdrive in the final seven minutes to wrap up a 31-14

victory. Since the Rams trailed as the clock ticked down, they were forced to try higher-risk, higher-reward plays which only rewarded the Cardinals.

Cornerback Patrick Peterson had his first two interceptions of the season in the fourth quarter – including his first career pick-six with 5:13 to play – and cornerback Antonio Cromartie returned a Kareem Martin-forced sack-fumble 14 yards to the house with 3:58 left for the final margin.

The Cardinals finished the game with six sacks and the three forced turnovers, making life tough on St. Louis quarterback Austin Davis.

"It's killing our defense," Davis said of the defensive touchdowns allowed. "They're playing their tails off. For us, for me, to have those letdowns, it's really tough."

Peterson said the Cardinals' defense didn't have the right focus early on, as it allowed a long touchdown drive in the first quarter and then a 59-yard scoring strike from Davis to tight end Jared Cook before the half.

The second half was a different story. Following a Carson Palmer interception late in the third quarter, the Rams moved the ball inside the red zone, but a St. Louis penalty – negating most of a long gain -- and a sack by Calais Campbell turned a minimum of three points into a punt.

When Palmer suffered a knee injury early in the fourth quarter, the defense played even better.

"We were playing kind of angry because those guys were getting after our quarterback," Peterson said. "As a defense, we were kind

of watching it happen. We felt that we came out flat. We didn't play with any intensity. We didn't match their intensity because as a defense, we felt that, obviously their offense can't beat us, so we felt that we were playing against their defense. We came out on top."

The Cardinals have consistently held opposing offenses to low point totals, but this one may have been the most thorough defensive performance of the season. The pass rush nearly doubled its season sack output – from eight to 14 – the total yardage allowed (244) was low and the turnovers were there.

"We got into the zone, got the momentum on our side and left it all on the field," said defensive end Calais Campbell, who had a pair of sacks.

Cromartie helped cap the victory with the fumble return for a touchdown, but he was still concerned about the start. While the Cardinals have made a habit out of fourth-quarter comebacks, he'd rather see the intensity from start to finish.

"We have to come out and show who we are, not do it in the last 15 minutes or the second half, or play hard in the first half and give up a touchdown at the end of the game," Cromartie said. "It's a point of coming out and doing the things we are supposed to do as a team and put 60 minutes together, because there may be a game that we may not be able to do the things we need to do correctly. We will have those games."

There's no denying, though, how well the defense plays in the second halves of games. Whether it is adjustments by defensive coordinator Todd Bowles or simple will-power, the team has given up only 71 points after intermission, an average of 7.9 per contest.

"We know just keep sawing wood and we'll have a chance at the end," Campbell said.