Quarterback Kevin Kolb fires a pass to Larry Fitzgerald last weekend. Kolb is in the top 10 in the NFL in passing and has led the Cards to a 4-0 start despite not winning the starting job coming out of training camp.

Red-zone work was the focus, as it typically is with every Friday practice, and unbeknownst to quarterback Kevin Kolb, the Cardinals were working on the play that ultimately saved their game Sunday – a double-move route that took receiver Andre Roberts to the front left part of the end zone.

The pass was executed flawlessly against the Dolphins for the game-tying touchdown. But Friday, Kolb threw it about a half-count earlier and too high. Roberts, with the timing off, couldn't adjust.

"From Friday's rep to Sunday's rep, the difference was maybe six inches and not even half a second," quarterbacks coach John McNulty said. "That's the difference between a touchdown and incomplete. It was neat to see."

Kolb might have not been able to make that play a year ago. He might not have been able to make it six weeks ago. The quarterback he was isn't the quarterback he has become, but, like his throw to Roberts, the difference was never vast. An overhaul wasn't needed. It was smaller details – an understanding of a play here, a step up in the pocket there – that held him back.

"That's how small the room for error is in the NFL," Kolb said.

In three starts and a quarter – having come in in relief of the injured John Skelton late in the opener – Kolb is ninth in the NFL in passing rating (97.6), has thrown seven touchdown passes and just two interceptions. His passing rating on third downs is 120.2, second in the NFL, and that doesn't include his two clutch fourth-down completions on the game-tying drive against Miami (video below).

Kolb had three touchdown passes and 324 yards against the Dolphins, the best he has done in each category in a game since coming to Arizona.

Wide receiver Larry Fitzgerald said the coaching staff has done a better job adjusting to Kolb's abilities – "That's what makes coach Whisenhunt a great coach, he doesn't try and put a square peg in a round hole," Fitzgerald said – and McNulty said Kolb clearly has a mastery of the offense that he did not have in 2011 when he was coming into training camp cold because of the lockout.

But the key, named by every player and coach talking about Kolb, is confidence.

"He definitely has more confidence now," Roberts said. "He went through a lot last year. That whole thing with the quarterback competition I'm sure was in his mind. But he stayed consistent and stayed the person he knows he can be."

That's a natural by-product of understanding the offense. Kolb knew he was going to have to learn how to play with the Cardinals and "evidently, it's taken some time." He said this isn't the first time he's had this kind of confidence, but he's still trying to manage the quarterback's requirement of not getting too high or too low.

At this point, it's feeding into itself.

"The more plays you make, the more victories you get and the more experiences you go through, it gives you the confidence you can handle things," Kolb said.

Kolb has been better in the pocket, and McNulty said the times when Kolb has left the pocket it's mostly been for a good reason and been a good decision. When he makes mistakes, Kolb is able to brush it off easier, coach Ken Whisenhunt said, and that too has been for the greater good.

Kolb not only has a better grasp on the offense but he provides ideas that have helped the game plan, McNulty said. His practice work has been carrying over into games.

"Even with the interception Sunday when it took the breath out of the stadium, he just came over and matter-of-factly said, 'I can't do that. That was dumb.' That was it," McNulty said. "Same thing when he threw the touchdown to Andre earlier. He gets excited but he brings up, 'On the third play of the drive, I should have done this.' He's been even-keeled, whether it was losing the starting job, getting it back, bad play, good play, it's all the same. Which is good."

The approach doesn't shock teammates.

"It's not like he's walking around here with a fat head," center Lyle Sendlein said. "He's a humble guy, but he expected to have success and he's handled it well."

Kolb has repeated multiple times he wants to avoid looking too far into the future. It doesn't look like his starting job is changing anytime soon, even with John Skelton finally returning to full practice after his ankle injury, but Kolb knows this game doesn't lend itself to permanence.

One detail at a time. That's what got him to this point. No reason to change now.

"I wish last year could've been better," Kolb said. "But that's behind us now. We're making strides in the right direction."