The Toffees went down 2-0 to the Canaries at Goodison Park but the Dutch manager was not too perturbed as it was simply a case of being a little unlucky in front of goal.
After the match, Koeman praised the hard-working nature of his players, some of whom had little game time before the Norwich encounter.
"All of them worked very hard tonight," he said.
"It's always difficult for these players. They did not play a lot at the start of the season and you can't analyse them by one match.
"Everybody is working hard to get the chance and to play, but it's the whole team performance. If you see the second goal, it was a great goal but bad defending from four or five players - some who have played regularly.
"It's always the whole team that is doing well or is not clinical enough. But, once again, I'm not disappointed in my players.
"It's worse if you think the team did not work hard, did not press or did not do what we spoke about before the game - then it's a problem. But this is not a problem tonight."