The Ligue 1 champions trailed to an early Adamo Coulibaly goal before fighting back to collect all three points in a match which saw three men sent off, and Blanc believes that his players could have won by a bigger margin on a different night.
"We didn't start the game too badly, but when you make chances and don't take them, and then concede on a 60-metre-long counter-attack, you tell yourself that you're in a difficult period when every mistake you make costs you a goal," the PSG boss told reporters. "But there was also the reaction of my team, which allowed us to equalise and even take the lead.
"Paris controlled the game and Lens tried not to concede a fourth goal after the things that happened. I would have liked my team to be more ambitious. In the second half, I think we could have scored a fourth, but I'm happy with the three points."
PSG now turn their focus to the Champions League as they prepare to take on APOEL on Tuesday.