With qualification already assured from Group C, head coach Blanc took the opportunity to rest several key players, including Zlatan Ibrahimovic and Thiago Silva.
And that decision proved costly fpr Blanc as the Portuguese side secured a 2-1 victory at Estadio da Luz on Tuesday, although they still failed to qualify for the last 16 following Olympiakos' 3-1 win over Anderlecht.Blanc pinpointed a dip in his side's display after the break as the reason for the loss, although he remains confident that PSG can go far in the competition.
"I am disappointed with the performance of my team in the second half," he said. "It is the second half where we had a problem.
"We lacked a bit of ambition and Benfica played (well). For what they created in the second half they deserved the win.
"There has, of course, been lessons, both individually and collectively. Hopefully PSG will be able to win the Champions League but before that there will be plenty of games to play."