Cardinals quarterback Carson Palmer (right) and coach Bruce Arians strategize during the win over the Browns

Any way you dice it, the Cardinals were one of the best teams in the NFL in the first half of the season.

They won 75 percent of their games, finished third in total offense and fourth in total defense (the only team in the league top-5 in both). While they had momentary troubles, most of the issues were minor and didn't reoccur.

"We can run the football, we can throw the football," wide receiver Larry Fitzgerald said. "We can stop the run, we can stop the pass.  I don't feel like we have a definitive weakness where teams can really exploit us."

Now the Cardinals must prove all those areas can remain strong against stiffer competition.

The Cardinals are categorized as Super Bowl contenders because, in many ways, a 6-2 start underestimated how good they were in the first half. If they didn't lose the turnover battle 3-0 against St. Louis, that outcome could have turned out differently. If they didn't blow myriad first-half chances to distance themselves from the Steelers, that game could have been won.

The Cardinals have a point-differential of plus-110, which is second in the NFL behind only the Patriots, and that's why even a two-game lead in the NFC West and a spot among the NFC elite isn't completely satisfying.

"You're happy to be 6-2, but you can't help but think about that '2' that's hanging after the '6,'" quarterback Carson Palmer said.

While the Cardinals consistently impressed through the first two months, the caveat was that the competition wasn't good. The Cardinals' opponents were 21-42 over the first eight weeks, a .333 winning percentage.

The strength of schedule changes in a hurry in the second half. First up is this week's "Sunday Night Football" affair with the defending NFC champion Seahawks, with a second matchup against Seattle set for the season finale. The Cardinals also play the undefeated Bengals, the Rams, the Vikings, the Eagles and the Packers. The easiest game is against the 49ers, and even they have been demonstrably better at home.

"If we can go these next eight games 6-2 I think we'll all be happy," Fitzgerald said. "We've got a really tough challenge coming down the road. We understand that, but I think we're ready for the challenge. We're excited about it."

The Cardinals have lamented lulls and missed opportunities during the first half of the season. The final two sleepy quarters against the Steelers were the most maddening because they resulted in a loss, but there were also some missteps that came in victories.

The Cardinals turned the ball over consecutively late in the second quarter against the Bears and had a poor first half in Cleveland. The team was high-powered enough to overcome those blunders, but the margin of error is now slimmer.

"We can't have those types of halves," Fitzgerald said. "We can't have those types of quarters. We can't have those types of series if you expect to be competitive against these types of ballclubs. We understand, and hopefully we can learn from the mistakes that we made early on in the season."

Said Palmer: "Those lulls, you can get away with them in some of the games we've gotten away with them. Coming up, we can't afford those lulls."

Not everything can be pinned on the Cardinals, as there are always highly talented players on the opposition whose job it is to disrupt the game plan.

"We're capable of playing at a very high level," coach Bruce Arians said. "When we don't, you want answers and reasons. Sometimes the other guy on the other side is pretty damn good."

As the regular season hits its stretch run, the guys on the other side will be even better. If the Cardinals' prolific season is to continue, the game-changing mistakes must be kept to a minimum. No more halves like the opening two quarters against the Browns, and much more of the post-intermission juggernaut.

"That's a 5-11 football team right there in the first half," Fitzgerald said. "And then you come out in the second half and show what we're capable of."