TEMPE, Ariz. -- The fourth quarter has become more than just the final 15 minutes of the game to the Arizona Cardinals.

It’s turned into the real difference between winning and losing. Heading into their ninth game, the Cardinals have scored 122 points through three quarters. But so have their opponents.

Remember the cliché used by youth coaches that the game is 0-0 at halftime or the end of the third quarter? It’s become a reality for the Cardinals. They have outscored opponents 70-34 in the fourth quarter this season, largely because of quarterback Carson Palmer. And their plus-36 point margin in the fourth is the best in the NFC and trails only Kansas City’s plus-37 for the highest in the NFL, according to ESPN Stats & Information,

Palmer is second in the NFL in fourth-quarter total QBR (86.1) and fourth-quarter touchdown percentage (8.7), according to ESPN Stats & Information. In his five games this season, he’s one of four qualifying quarterbacks without a fourth-quarter interception. The other three are Buffalo’s Kyle Orton, Tampa Bay’s Mike Glennon and Minnesota’s Teddy Bridgewater.

In the fourth, Palmer is completing a higher percentage of his passes than the previous three quarters (65.2 vs. 60.6), and is averaging more yards per attempt (7.65 vs. 7.27). He’s thrown four touchdowns in the final quarter this season, compared to seven combined in the first three.

"We’ve been a second-half team since I’ve been here, as long as I can remember being a Cardinal," Palmer said. "We were a second-half team last year. We were really a second-half-of-a-season team last year, obviously, but we’ve been really good in the second half.

"And it’s good and bad. It’s good because that’s when games are won, but it’s bad because you leave teams hanging in the first half when you don’t go out and execute the way you expect to. From that standpoint, there are a lot of things we can clean up. We started hot and started fast as the season started, but we haven’t started games fast, and that’s something we all are looking to improve."

Palmer gets some help in the fourth, however.

Arizona’s defense looks like a different unit during the final 15 minutes:

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Six of the Cardinals’ 12 interceptions, three of their eight sacks and three of their four fumble recoveries have come in the final quarter. Their plus-8 turnover margin is the final quarter is the best in the NFL.

In the fourth quarter Sunday in Dallas, Arizona held the Cowboys on fourth-and-1 with 9:41 left in the game, giving the ball back to the offense, which then extended a 14-10 lead to 21-10. It added another touchdown later in the game.

"That’s the way it’s been all year," Cardinals coach Bruce Arians said. "We kind of do some things, and I’ll take some shots sometimes that if we don’t hit, they’re going to put us behind the chains. We’ve been doing a better job of still making first downs after those, but we have to do a better job."