ESPN College Football

Rudy Carpenter's numbers are up, and so are the corners of his mouth. If you were the Arizona State quarterback who had rebounded from a difficult season to take your team into the heart of the national championship scrum, you would be smiling, too.

"I feel good. We're 7-0. We're No. 4 in the BCS," Carpenter said in a phone interview this week, as No. 4 Arizona State (7-0, 4-0) prepared for a Saturday night game against No. 21 California (5-2, 2-2). "We're one of the few teams that can control our own destiny. That feels good."

A warm bath always feels better after coming out of the cold. The Sun Devils' 7-6 record last season didn't leave Carpenter and his teammates disheartened as much as it revealed their problems.

"We were struggling in games," safety Troy Nolan said. "When somebody gave up a long play, we would come back to the sideline arguing."

Out went coach Dirk Koetter, a man who continues to be well-regarded on the Arizona State campus. In came Dennis Erickson, with a reputation as a carpetbagger and a winner. He has fulfilled the latter (only time can disprove the former) with constant positive reinforcement, a simpler playbook and more communication.

Nolan said the message from defensive coordinator Craig Bray has been simple: "Play hard. Play physical. Play fast. … We tell them what we feel will make us play better. They've given us leeway out there."

The story is similar on offense, and the most obvious example of it is Carpenter, the 6-foot-2, 199-pound junior who has had several careers in his time at Arizona State.

"Coach Erickson has got us upbeat and working hard," Carpenter said. "I think I have really played more relaxed. I haven't been thinking and overanalyzing. Coach Erickson makes me feel like, 'Just do what you do,' and he's positive that if I do that, that will be enough."

Confidence is a contagion, as is the lack of it. The biggest carrier on the offense -- and, often, in the locker room -- is the quarterback.

"He's putting the ball in the air and giving us the chance to make a play," senior wide receiver Rudy Burgess said of Carpenter. "Last year, he had a big problem with guys dropping the ball. He told us he needed to find a guy to count on."

"His swagger has changed," Nolan said. "He's fairly confident. … He's our man. He's our quarterback. I saw it in the spring. He had that good season in 2005 when he filled in for Sam [Keller]. He wanted to prove himself. I saw it coming in the spring. He wanted to prove himself this year."

Between 2005, when Carpenter filled in for the injured Keller and led the nation in passing efficiency (175.01 rating, 17 touchdowns, two interceptions), and this season, the Sun Devils' first 7-0 start since the Rose Bowl year of 1996, came the struggle of 2006.

Carpenter had a soap opera dumped in his lap by Koetter, who named Keller the starter in the week before the opener, changed his mind the following day and gave the job to Carpenter. Keller responded with an immediate transfer to Nebraska. Carpenter responded with a performance that was textbook in its mediocrity.

His yards per game fell by more than 20 percent, from 252.6 to 194.1. He threw 14 picks in 13 games. Arizona State gave up 37 sacks, so many that Carpenter said last spring, "It starts to wear on you a little bit."

This season, Carpenter's passing numbers are up, nearly approaching the zone he approached two years ago. He is completing two of every three passes (132-199), his touchdown-interception ratio is healthy (16-7) and his rating (158.9) is back where Moody's would give him an Aaa. The only thing that's unchanged is the sacks. Arizona State already has given up 26 sacks this season, 113th in the nation.

"My body is holding up good," Carpenter said. "Winning has a lot to do with that."

Winning -- it cures what ails you.

The newfound self-confidence has been a beacon in some difficult games. Arizona State trailed Colorado 14-0 late in the second quarter and won 33-14. Arizona State trailed Oregon State 19-0 in the second quarter and won 44-32. The Sun Devils won 23-20 at Washington State by kicking a field goal in the final minute.

Only teams with faith in themselves pocket those kinds of victories.

"We had to find a way to win," Carpenter said of the Oct. 6 victory over the Cougars. "Right now, that's our prove-it moment. We know we've got some really good teams ahead of us. We're trying to earn respect week by week."

California comes to Sun Devil Stadium having lost two consecutive heartbreakers. Arizona State plays at home, after a week off, buoyed by success that only the most optimistic Sun Devils fan would have predicted.

After this week, Arizona State plays consecutive road games at No. 5 Oregon and at Pac-10 co-leader UCLA before a Thanksgiving night home game against No. 12 USC. It's a schedule that would test anyone's faith.

Arizona State, at long last, has faith to test.

Ivan Maisel is a senior writer for ESPN.com. Send your questions and comments to Ivan at ivan.maisel@espn3.com.