Juve won 3-2 in Norway, with Lois Openda, Weston McKennie and Jonathan David (penalty) the goalscorers for the visitors.
Capello said on Sky Italia: "Yildiz made the difference, he caused problems for Bodo in every way. They couldn't stop him, he was a leader with quality.
"And I would highlight the fact that both strikers scored. And this means a lot psychologically for the players. We knew Yildiz was good, but now Openda and David have also unlocked themselves."
Yildiz didn't get onto the pitch until the start of the second-half.
The midfielder said afterwards: "Before the match I didn't know I wouldn't play. When I came on I wanted to do my best, and I'm happy to have helped the team win, regardless of the goals or assists.
"Today's three points are very important."