Blanc's side led the tie 3-1 going to Stamford Bridge, but they were knocked out when Demba Ba's close-range goal in the 87th minute levelled the aggregate score at 3-3.
Andre Schurrle had pulled a goal back for the hosts in the first half, and the German hit the bar, as did Oscar with a free kick, after the break.
PSG exited Europe's elite club competition on away goals in the last eight for the second successive year and have yet to make an impact in Europe since they were bought by the Qatari Investment Authority in 2011.
"Overall, in my opinion, the difference was not huge," Blanc told UEFA's official website.
"We could have gone through but, unfortunately for us, it's Chelsea who do. But the level of both teams, in my opinion, was very close.
"Over the two matches there was very little between the two sides - ultimately, though, I think Chelsea's experience of playing at this level of the competition made the very small difference."
The French side looked comfortable early on, but Edison Cavani failed to hit the target when bearing down on Chelsea goalkeeper Petr Cech with the tie still poised in PSG's favour.
Cech saved from Marquinhos deep into stoppage time, and Blanc pinpointed his side's failure to convert their few chances as crucial in the final analysis.
"Ironically, we started better in the second leg than the first. In the first 25 minutes we were fine.
"We conceded a key goal from a throw-in and that put us in big trouble, giving confidence to Chelsea.
"Then, in the second period, they tried to pile pressure on to make us suffer. Unfortunately we did not take our chances."