All year long, Stanford struggled to play complete games.

Against Arizona State in September, the Cardinal jumped out to a 22-point lead only to allow the Sun Devils score three straight touchdowns. Against Utah in October, the Cardinal sleepwalked through most of the game before a furious fourth quarter fell just short. And against Oregon on Nov. 7, Stanford played its best football of the season for three-and-a-half quarters, but still let the Ducks claw their way back to make the game come down to an onside kick.

But on Saturday night, there was no doubting that No. 7 Stanford (11-2, 7-2 Pac-12) played a complete game on the conference’s biggest stage to defeat No. 11 Arizona State (10-3, 8-1) 38-14 at Sun Devil Stadium and defend its Pac-12 title. The Cardinal booked its return trip to Pasadena for the Rose Bowl Game — the 100th Rose Bowl Game, no less — and will be going to its fourth BCS bowl game in as many seasons.

“I told the players what was at stake,” said head coach David Shaw. “What was a stake was their legacy.”

Ever the workhorse, senior running back Tyler Gaffney responded to his coach’s challenge by rushing for 133 yards — his ninth 100-yard game of the season — and three touchdowns on 22 carries. In the process, Gaffney passed Stepfan Taylor ’13 for second all-time Stanford single-season rushing yards. Gaffney was watching from the stands when the Cardinal secured a Rose Bowl berth on a rainy night in Palo Alto last year, but by the end of Saturday night, Gaffney was celebrating with his teammates atop the podium and clutching the Pac-12 Championship Game Most Valuable Player trophy in his hands.

“It’s unreal,” Gaffney said. “Just to have the opportunity to be out there — you can’t even explain it. I love being out here with Stanford guys. This is why I came back. Being on this stage is why you came back.”

The Cardinal offense didn’t get off to a good start after Gaffney slipped on the first play and a subsequent false start penalty put Stanford in a second-and-17 hole. But just when it seemed like the offense was going to suffer the same early-game struggles that it was plagued by in last month’s loss at USC, Gaffney bounced to the outside and broke loose for a 69-yard touchdown run.

Coming into the game averaging 49 points per game at home, Arizona State answered on its first drive when running back D.J. Foster scampered through a gaping hole in the middle of the field to score a 51-yard touchdown. A rare mistake by the Cardinal defense, it was the longest running play that the unit had given up all season.

But, in a reversal of roles for shutdown Stanford, the Cardinal offense stepped up.

After being criticized for his poor road performances against Oregon State and USC, junior quarterback Kevin Hogan was accurate from the get-go, highlighted by his 42-yard completion to junior wide receiver Devon Cajuste late in the first quarter. Hogan showed great poise in front of a hostile crowd, as he lead the Cardinal into the end zone on its first four drives.

Two more Gaffney touchdowns sandwiched a 22-yard end-around touchdown run by junior wideout Ty Montgomery to give Stanford a 28-7 lead early in the second quarter.

“It’s all about toughness,” Gaffney said. “Execution and toughness. Falling forward and getting those extra yards — not letting guys bring you down.”

The Sun Devils started to bring down Hogan for sacks midway through the second quarter to stop Stanford’s scoring spree and get the ball back into their offense. The most explosive player on the field in the first half, Foster caught a short pass from quarterback Taylor Kelly, made junior safety Jordan Richards miss and took it to the house for a 65-yard touchdown that made the score 28-14 at halftime.

But that would be Arizona State’s last points on the night.

ASU’s offense drove down to the Cardinal 14 on its first possession of the third quarter, but Zane Gonzalez, who had made 18 consecutive field-goal attempts coming into the game, missed a 31-yard try just wide right. Senior kicker Jordan Williamson fared better for the Cardinal, as he nailed a 30-yard field goal — his first field goal attempt in the state of Arizona since the Fiesta Bowl disaster — on the ensuing possession.

For the rest of the game, the Cardinal defense was in full control and even made a goal-line stand — aided by fifth-year inside linebacker Shayne Skov timing the snap perfectly on third down and sophomore safety Zach Hoffpauir making the biggest tackle of his career on fourth-and-goal — to hold the Sun Devils scoreless in the second half.

Coming into the game with eight 250-yard passing games, Kelly was limited to just 173 yards through the air. The Sun Devils’ ineffective passing game was a big a reason why they were only able to convert 5 of 16 third downs on the night.

Following the goal-line stand, the Cardinal put the game away with a 99-yard touchdown drive. On third-and-6 at the Stanford 5-yard line, Hogan threw a perfect deep ball to Cajuste, who took the pitch-and-catch for a 78-yard gain. Three plays later, Hogan threw a dart to Montgomery for a 24-yard touchdown that gave Stanford a 38-14 lead with 12 minutes left in the game.

Averaging 23.1 yards per completion, Hogan would finish the game 12-of-18 passing for 277 yards and a touchdown.

“The bottom line is if the team tries to stop the run, we have to make big plays in the passing game,” Shaw said.

Arizona State couldn’t even cross midfield in the fourth quarter. Though the Cardinal defense saw its turnover streak snapped at 36 games, the unit sacked the Kelly three times in the fourth quarter to destroy any hopes of an ASU comeback.

“We stayed aggressive,” Shaw said. “We stayed aggressive the whole time.”

With its second straight Pac-12 title under its belt, Stanford will now prepare to play against Big Ten champion Michigan State in the 100th Rose Bowl Game on Jan. 1. The Cardinal moved up to No. 5 in the AP Poll and No. 7 in the Coaches Poll on Sunday morning; the Spartans are No. 4 in both.

Contact George Chen at gchen15 ‘at’ stanford.edu.