DURHAM, N.C. (AP) -- Brian Cobbs ran for two first-half scores and Army converted four turnovers into touchdowns to beat Duke 35-21 on Saturday.
Trent Steelman threw for two scores and ran for another for the Black Knights (3-1), who snapped a seven-game losing streak against Atlantic Coast Conference teams. Army jumped to a 14-0 lead in the first quarter, a margin that allowed it to stay with the yard-churning and clock-controlling triple-option offense against a Duke team still reeling from last week's ugly loss to top-ranked Alabama.
The Blue Devils (1-3) got off to a horrendous start with Sean Renfree throwing two quick interceptions, then watched things get worse the rest of the afternoon.
Army led 21-7 at halftime, then Steelman ran perfectly executed play-action fakes on TD tosses to Raymond Maples and Austin Barr to push the lead to 35-7 in third quarter.
Duke's defense did little to slow the Black Knights. No defender was within about 5 yards of either Maples or Barr on those second-half scoring passes, while Army's ground game ran for 333 yards and helped the Black Knights control the clock for nearly 40 minutes.
Duke coach David Cutcliffe talked through the preseason about the youth of his defense, but it was the surprisingly inept play of Renfree and the offense that had to befuddle the third-year coach most. Stephen Anderson jumped in front of Renfree's short pass over the middle and returned it to the 3-yard line, setting up Cobbs' first score barely a minute into the game.
Then, after the Blue Devils went three-and-out, Donnie Dixon grabbed another bad throw from Renfree and returned it to the 5, setting up Steelman's keeper two plays later and leading Cutcliffe to immediately walk to his quarterback and talk to him on the sideline.
Army coach Rich Ellerson had said he had visions of Duke's passing attack being able to move the ball up and down the field, yet Steelman came up with big pass plays long before Renfree. After Conner Vernon fumbled away a catch, Steelman connected with Maples for the 34-yard score, then added the 31-yard touchdown to Barr when Renfree fumbled while scrambling despite being untouched to make it 35-7.
The Blue Devils didn't manage the kind of big play they desperately needed until Renfree found Vernon for a 58-yard touchdown on the first play of the fourth quarter. But after Renfree threw a third interception with about 5 minutes left, Cutcliffe could only greet his first-year starter as he walked off the field, put both hands on the sophomore's shoulder pads and have a long discussion on the sideline.