The Swedish striker scored twice in the second half to lead PSG to a 2-1 comeback win against Ligue 1's bottom team Nancy at home on Saturday.
"People are very demanding in Paris," ESPNSoccernet quotes him as saying. "It is a bit bizarre when you think of what things were like before. Because, before, there was nothing.
"Try and play these games yourselves and then you will understand. I have played for lots of clubs and won titles everywhere but it is never easy to win games like these.
"We always want to win playing good football but it is not easy. We do our best. Sometimes we don't achieve the objectives we set ourselves. That's life. We are human beings. You (the media) make lots and lots of mistakes and so can we sometimes."
PSG are currently four points clear at the top of the Ligue 1 table.