Edinson Cavani scored an 87th-minute winner for the Ligue 1 giants as they left Cyprus with all three points in the UEFA Champions League.
Donis said his team had appeared the more likely winners before Cavani's goal kept PSG top of Group F.
"We are upset with the result but we feel fortunate that these players work so hard to represent this team in the best possible way," he said.
"Against Paris, taking into account the chances, we were the ones who were close to sealing the win.
"But unfortunately, in one instance, David Luiz saved a clear goal off the line and then moments later, following confusion in our box, Cavani managed to score."
Donis denied the result had come down to luck or was an injustice, but he was proud of how his team had made it difficult for PSG.
"I don't believe in justice or luck when it comes to football. It's a sport and there are always deciding factors," he said.
"My players work very hard to prepare for these games and need to use all their strength against some of the best teams on the planet.
"Not only do they manage to achieve that, but they also make life very difficult for these great clubs."
