Every week throughout the football season, the Blue Zone will break down a player on each team who could be the difference-maker in the upcoming contest. Following its victory over Army, Duke travels to Evanston, Ill. for the team’s first road test of the season, where they will face Northwestern. Here is our Evan Kollin's X-Factor for the contest:

Duke: Linebacker Joe Giles-Harris

One of the major forces behind the Blue Devils’ lopsided win over Northwestern last fall was their ability to contain the run. Duke limited their Big Ten foe to just 22 rushing yards on 21 carries, the Wildcats’ lowest output of the season. One of the leaders of that suffocating defense was now-captain Joe Giles-Harris, who placed second on the team with six total tackles in the contest.

Giles-Harris, the 2017 Carmen Falcone MVP as Duke’s most outstanding player, recorded 125 tackles last season, good for No. 16 in the FBS. That breakthrough campaign led to the redshirt junior’s designation on the 2018 preseason All-ACC team as well as the two votes he received for preseason ACC Player of the Year. The Nyack, N.Y., native posted a respectable seven tackles in the season opener, but he will need to step up to stop Northwestern on Saturday.

Northwestern torched Purdue for 166 yards on the ground, including four rushing touchdowns, in their season-opening win. The Blue Devils’ defense will be reliant on Giles-Harris’ reads and leadership in stopping this prolific rushing attack.

Northwestern: Running back Jeremy Larkin

Last season, Northwestern’s run game was spearheaded by Justin Jackson, the Wildcats’ all-time leading rusher. But with Jackson now gone, it is Jeremy Larkin’s time to shine.

Larkin showed off his ability in limited work last year, averaging 6.0 yards per rush over his 84 carries last season behind Jackson. Against Purdue in Northwestern’s opener, he took advantage of finally having the backfield to himself—the redshirt sophomore totaled 143 yards on 26 carries, including two rushing touchdowns, as well as four catches for another 20 yards.

Although the Wildcats were unable to get anything going on the ground during their last meeting with the Blue Devils, Northwestern must make Jeremy Larkin a focal point and attack the formidable Duke rush defense early and often.