Having amassed a 4-0 lead from the first leg, the French champions were in little danger of crashing out of the competition at the last 16 stage against Sami Hyypia's men in the return fixture on Wednesday - even when they went a goal down to Sidney Sam's early header.
While the hosts equalised through Marquinhos shortly afterwards, Leverkusen captain Simon Rolfes then saw a first-half penalty saved before Ezequiel Lavezzi eventually ensured PSG a 2-1 victory on the night with his second-half winner.
That was enough to comfortably book Blanc's men a place in the last eight - while the Germans ended the game with 10 men after Emre Can was sent off for a second bookable offence.
But despite their 6-1 aggregate progression, Blanc was still disappointed with the way his side began the game.
"We have not seen a fantastic Paris tonight, but we were able to raise our game in the second half to win," he told Infosport.
"Given the composition (of the side), it lacked experience and it showed. But it was powerful enough to win this game."
The victory puts PSG into the quarter-finals of the Champions League for the second year running. However, Blanc has played down their chances of lifting the trophy, insisting that they are not among the favourties.
"I'm not talking about that," he added.
"Clubs have experience and culture of the Champions League that is superior to ours: Bayern (Munich), Real (Madrid), Barcelona. They have experience that we do not have.
"But with the games we have played, people take us seriously."
