Romelu Lukaku and Khvicha Kvaratskhelia struck the goals for the 2-0 win on Tuesday night.
Fonseca said afterwards: "I think those who played played well. I don't look for excuses, I believe in all the players. And today they showed it. We can say that important players are missing, but I don't know if with them we would have done better than today because those who played did well.
"I expected a few more points. I didn't expect so much difficulty in changing the way we play, even if this change is starting to show. They scored two goals with two chances. We did a lot of positive things. We failed to score on the opportunities we created. What I'm looking at is the growth of the team. We have to improve in defense. But I've never seen any team that has put the offensive quality we put on the field today."
On Leao, he continued: "I don't want to go into details. I handle things with the players differently. There is no conflict between us, it's just a coach's option. We try to motivate the players in different ways. Then it's up to the players to put in the right amount of dedication: I don't have to beg them.
"I wasn't referring to Leao when I spoke about dedication. It's difficult to play with three wingers. Pulisic doesn't play in Leao's position, Okafor does. Today Leao came in well, he gave good answers. Then if we're honest, let's look at Okafor's game, he played well. It's difficult for me to decide at this moment. Leao is coming back to get back into the lineup, for me this is the most positive thing."