EVANSTON, Ill. -- Daniel Jones dropped back to pass when he got driven to the ground by a blindside hit.
He came down on his left side and left the game with an injured clavicle, which could mean a lengthy absence for the star quarterback and a huge loss for Duke.
Jones threw for three touchdowns before getting knocked out of the game, and the Blue Devils beat Northwestern 21-7 on Saturday.
Coach David Cutcliffe said it "doesn't look great" and was bracing for his quarterback to miss a big chunk of time. He added Jones would be examined when the team returned home.
Cutcliffe doesn't expect star cornerback Mark Gilbert to return anytime soon, either, after he exited with an injury to the left hip area in the second quarter.
Those were two big losses on a day when the Blue Devils (2-0) beat the Wildcats (1-1) again after pounding them at home last year.
Jones completed 16 of 22 passes for 192 yards in another big game against Northwestern. He accounted for 413 total yards and four touchdowns in last year's 41-17 romp.
"He was playing lights out," Cutcliffe said. "He's prepared hard. And that preparation, you can visibly see it. Anybody can see it. A lot of confidence. He's not through, so we'll be cranking it up moving forward."
Jonathan Lloyd had 94 yards receiving, including a 52-yard touchdown catch in the second quarter. Davis Koppenhaver had a one-handed TD grab late in the first half, and the Blue Devils won for the 21st time in 24 games against non-Atlantic Coast Conference opponents.
Northwestern's Clayton Thorson was 22 of 38 for 198 yards and an interception in his second game back from a torn anterior cruciate ligament in his right knee. He again shared time with TJ Green, who went 9 for 18 for 84 yards and an interception.
Thorson said he was feeling good after taking some hits to the lower body. But the medical staff is determining his playing time.
"I wish I had control over that," Thorson said. "I'm just told whether or not (Thorson) is in or (Thorson) is out."
Jeremy Larkin ran for 121 yards and a touchdown after going for a career-high 143 in the opener against Purdue. Flynn Nagel had 12 catches for 133 yards -- both personal bests. But the Wildcats lost for the first time since Penn State beat them last Oct. 7.
Duke: The Blue Devils could be in trouble if they have to get by without Jones and Gilbert.
Northwestern: The Wildcats clearly need a healthier Thorson if they're going to make a run in the Big Ten. Larkin, meanwhile, showed again he's ready to become the workhorse running back with career rushing leader Justin Jackson in the NFL.
"It's always good to get wins against Power Five schools and great competition. But we made a lot of mistakes, things that need to be fixed. We need to learn as much from a win as we do from a loss. This is a great tape to watch and get better and learn from." -- Lloyd on the victory.
Jones threw for 159 yards and three touchdowns in the first half to help the Blue Devils grab a 21-7 lead.
Northwestern's lone points came on the game's opening drive, when Larkin broke off a 40-yard run to the 4 and carried it in from the 2. But three TD passes by Jones in the second quarter gave Duke a 14-point lead.
He connected with T.J. Rahming on a 9-yarder just over a minute in and the Blue Devils scored on back-to-back possessions to go up 21-7.
Marquis Waters intercepted Thorson in double coverage, leading to the Wildcats' Cameron Green getting ejected for a helmet-to-helmet hit on him. Jones connected with Lloyd deep down the middle on the next play for a 52-yard touchdown to put Duke on top. An open Koppenhaver made it a 14-point game with 2:18 left in the half when he reached up with his right hand and hauled in a 9-yard touchdown in the back of the end zone.
Northwestern had a first down at the Duke 9 early in the third. But the drive stalled, with Thorson getting sacked on fourth down at the 4.
Duke: Visits Baylor on Sept. 15.
Northwestern: Hosts Akron on Sept. 15.
For more AP college football coverage: https://apnews.com/tag/Collegefootball and https://twitter.com/AP-Top25
Ron Johnson, ex-Giant and Michigan All-American, dies at 71
Former New York Giants running back Ron Johnson, who was the first black player to be a captain of the Michigan football team, has died. He was 71.
Heupel: UCF has elite players at skill positions
UCF head coach Josh Heupel speaks with SVP about the Knights' continued success and a primetime game vs. Cincinnati.
Contenders for SEC Coach of the Year
The Thinking Out Loud crew makes their picks on who would be their coach of the year from the conference.
Guarantano continuing to progress
Thinking Out Loud's Greg McElroy and Marcus Spears discuss how Tennessee continues to improve on offense and defense.
Williams: 'This is a unit, a family'
Texas A&M RB Trayveon Williams joins Thinking Out Loud to discuss how the Aggies have bounced back after two tough losses.
David Montgomery, Greg Roberts each missing first half of their teams' games Saturday
After a scuffle led to their ejections this past Saturday, Iowa State running back David Montgomery and Baylor defensive end Greg Roberts will miss the first half of their team's games this week -- vs. Texas and vs. TCU, respectively.