Hearts have all but lost their Europa League play-off tie after a 4-0 first leg defeat away to Dinamo Zagreb.
Jambos boss Csaba Laszlo pointed to the gulf in class and resources enjoyed by both clubs as the reason behind his side's heavy loss.
"If you lose 4-0, it is not okay," he told Hearts.TV.
"This is the biggest deficit that we've had under my regime here at Hearts.
"But we must look at the differences between the players.
"You saw the opponent at this level, at international level, he plays a different football."
Hearts were undone by Papadopoulos and the outstanding Pedro Morales.
Laszlo said: "You have two strikers which are at international level. They cost £12million-£15million and you saw why.
"We didn't play very well and Dinamo Zagreb were very good," he said, before promising fans an improved display in next week's second leg.
"The supporters have suffered more than anybody and I am also sad for the supporters.
"But I hope at Tynecastle we can give something back and I hope our supporters will also be at the next games.
"At the moment, definitely the team is in charge and we must look to win the next game at home."