The Turkey international featured in an unfamiliar position of wing-back in the World Football Challenge encounter at the Sam Boyd Stadium in Las Vegas.
Karanka was pleased with the versatility of Sahin and hailed his eagerness to play for the team.
"The important thing at this point is to play." he explained. "Nuri played at wing-back and did well.
"He is the first to want to play anywhere and get experience. The important thing is that there are no injuries and those who play help the team.
"We only have Fabio [Coentrao] on the left side and he is playing very well. Nuri is also ready."
Reflecting on the match that ended in a 2-1 victory for Madrid, Karanka stated: "It was a different game to the one that we played the other day against Los Angeles Galaxy.
"They are a team who have already started the league competition. It challenged us more than the last match, but the important thing is to keep building.
"It was a demanding match and with more physical contact."
Madrid's next game on their pre-season tour of the USA is on Thursday against Italian giants AC Milan.