A 2-1 loss away to Benfica prevented PSG from ending Group C unbeaten, though they still finished top of the standings.
The likes of Zlatan Ibrahimovic, Thiago Silva and Marco Verratti were rested with little riding on the game for the French champions.
But Blanc said at his post-match press conference: "Even though I left some star players in Paris, the starting 11 was strong. You only have to look at the number of internationals on the pitch.
"In the first half we did what we had to but in the second, we lacked ambition and Benfica took advantage.
"We are disappointed but we have to move on to other things. Don't forget, we qualified."
PSG led through Edinson Cavani but defender Marquinhos admitted a fightback - which came through goals from Rodrigo Lima and Nicolas Gaitan - was inevitable from a Benfica side still fighting for qualification.
The Brazilian told psg.fr: "It was a hard game, we expected that. Benfica are a good side at home.
"We played well in the first half but it was not enough."
Looking ahead to the last 16, Marquinhos is not concerned who his side may face.
"There is nobody we want to avoid," he said. "At this stage there are only big teams.
"If you want to go far, you have to beat everyone."
Those potential opponents will not include Benfica, whose comeback was in vain after Olympiacos beat eight-man Anderlecht to secure second place.