Al-Rayyan scored in the first half but conceded three goals in 12 minutes in the second half.
“We were good in the first half but after that we lost the game in six minutes,” lamented Blanc. “Although we scored first, the manner in which we conceded was a big blow to my players.
“The first 45 minutes were very positive for Al-Rayyan but Persepolis played very well, was physically better and applied pressure in the second half and it went on to score not one but three goals,” the Frenchman added.
“We had a player substituted due to a knock in the first half and then I decided to protect three of my players because we have another game in three days.
“I don’t know what happened to Al-Rayyan in the second half. It’s tough to lose a match like the way we did. We were playing well but lost our concentration in just six minutes.”