"I got it wrong against Real, but it was a red card out of frustration and sometimes referees could be more tolerant," he told 'Gazzetta dello Sport'.
"It was a bad reaction but I didn't insult anybody, whereas Messi goes around pointing his finger in the referee's face and doesn't even get punished. But anyway, I need to improve."
Verratti went on to discuss the match against Real, and the supposed gulf in class that exists between the two teams.
"PSG are not that far away from Real Madrid,' he added. "We were convinced we could go through, but then certain incidents make the difference.
"It [being without Neymar] is like taking Messi away from Barcelona -- they are players who make up 30 percent of a team.
"We're lucky to have him. He cost a lot because he's phenomenal."