Celtic have dropped 17 points this season, just four fewer than they did in the whole of last season, but the Greece striker is keeping positive.
He said: "We are the best team in the country. Everybody knows that. We proved it last year and we will prove it again this year as well.
"I know we are having ups and downs, I know there are negatives but I always see the positive things.
"We have one game against Spartak to get through to the last 16 of the Champions League.
"We are in the semi-finals of the Scottish Communities League Cup. I really don't see the problem."