Arizona State (10-2, 8-1 Pac-12) won last year's game by scoring 24 points in the fourth quarter and raced out to a 27-point lead by the midpoint of the second this time.
After scoring the second-most points in Territorial Cup history, Arizona State will host No. 8 Stanford in next Saturday's Pac-12 title game with a spot in the Rose Bowl on the line.
Taylor Kelly threw for 274 yards and two touchdowns, De'Marieya Nelson ran for two scores and the Sun Devils had no trouble without leading rusher and scorer Marion Grice.
The defense forced four turnovers, including a 64-yard interception return by Damarious Randle in the third quarter.
Arizona (7-5, 4-5) fell flat in trying to boost its bowl pedigree.
Ka'Deem Carey ran for 157 yards and a touchdown, but the Wildcats couldn't get out of their own way and had no chance of stopping Arizona State's offense.
Arizona's B.J. Denker had three interceptions after throwing four the first 11 games of the season.
The Territorial Cup is the oldest rivalry trophy in college football — dating to 1899 — and the 87th version had an added dash of hype, fueled by momentum and raised stakes.
Both teams were coming off their biggest wins in years: Arizona over Oregon and Arizona State over UCLA.
With the Wildcats in town and so much on the line, Sun Devil Stadium was packed, a buzz in the air like few times over the past several years.
The Sun Devils put on quite a show, too, running over and through the jittery Wildcats in the first half.
On offense, Arizona State didn't seem to miss Grice (injured leg), using a mix of pass and run to score on its first four possessions.
Zane Gonzalez made a pair of field goals, Kelly used a fake to set up Darwin Rogers for a 38-yard touchdown and Foster ran for 50 of 53 yards on a scoring drive he capped with a 14-yard touchdown run.
Nelson added his first career touchdown, a 1-yard run to put Arizona State up 27-0 midway through the second quarter.
The Wildcats didn't seem ready for the spotlight.
Arizona opened with delay of game penalty before getting off its first snap, went backward on its opening drive and gave Arizona State the ball at the 24 when Drew Riggleman shanked a 12-yard punt over ASU's bench.
After holding Arizona State to a field goal, the defense had a breakdown, biting on what it thought was a run play to leave Rogers wide open for a TD.
Denker then threw a ball up for grabs into double coverage, leading to an interception by Alden Darby that set up Nelson's TD run.
Arizona also had trouble getting Carey going, too — some of it apparently by design.
The nation's second-leading rusher didn't have a carry in the first nine minutes and was twice stopped on fourth down near midfield. On the first try, he lost seven yards, giving Arizona State a short field to set up Foster's touchdown run.
Trailing by 27, Arizona finally got some momentum going and marched in for a 1-yard touchdown run by Denker.
After Arizona's Jake Smith hooked a 42-yard field goal wide left, Gonzalez made one from 23 yards in the half's closing seconds, putting the Sun Devils up 30-7 while breaking the school record with his 18th straight made field goal.
Carey finally started to find some room to open the second half and scored on an 8-yard run.
It didn't matter by then.
Denker followed with another mistake, missing an open receiver downfield and throwing an underneath pass that Randle intercepted and raced in for a touchdown.
Arizona's Garic Wharton scooped up a fumble by Denker for a 4-yard touchdown, but Kelly answered by finding Jaelen Strong for a 61-yard touchdown that made it 44-21.
Foster scored on 7-yard run and Nelson went in from yard out, making it the most lopsided game in the series since Arizona State beat Arizona 56-14 in 1996.
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