The Italian was issued a second booking for a shirt-pull less than a minute after half-time but the Paris Saint-Germain coach insists that he is not angry with the 21-year-old
The Italian was booked in the first half for a deliberate handball before he was shown a second yellow card for a shirt-pull less than 60 seconds into the second period.
PSG went on to seal a 2-1 win thanks to Edinson Cavani's last-gasp goal and Blanc maintains that he will not come down hard on Verratti for his two indiscretions.
"The first booking, he deserved, but it wasn't a dangerous play. It's stupid but it stops the attack. Sometimes it helps the team," the coach was quoted as saying by RMC.
"Verratti made two mistakes in this game. I'm not trying to defend him but let's say it wasn't indefensible. I don't want to blame him, even though it put us in trouble."
Thiago Motta conceded that the red card made life "complicated" for the French champions but was proud of the way his side fought for the victory.
"We were cleary superior in the first half. [The sending-off] complicated life for us but the result was victory and qualification," the Italy international told Canal Plus. "We won with our heart. It was important for the team to win in these conditions."
Defender Maxwell compared the result to a 2-1 win over Olympique de Marseille in October, when PSG again battled to victory with a man down.
"It was the same again," the Brazilian added. "We lost an important player but we continued to play.
"We're very happy; we qualified, which is the important thing. We showed great strength, confidence, heart and desire."