The Wildcats (7-0) are off to their best start since 1993-94, when they won their first nine.
Shurna, a junior, became the 30th Northwestern player to surpass 1,000 points, finishing the night with 1,012. Luka Mirkovic added 11 points and 11 rebounds for Northwestern.
Both teams shot better than 50 percent in the first half, and Northwestern led 38-34 at intermission. The Wildcats outscored the Eagles 9-2 at the outset of the second half to take a 47-36 lead. Northwestern's biggest lead in the second half was 22 points.
This was the first meeting between Northwestern and American, which plays in the Patriot League.