Rangers defender Connor Goldson played down the gap between the Ibrox men and Celtic despite another Hoops Old Firm win on Sunday.
Olivier Ntcham's second-half strike handed Steven Gerrard his first defeat as Rangers boss in his first Glasgow derby.
The champions dominated the Premiership meeting at Parkhead and hit the woodwork four times with Gers keeper Allan McGregor making several good saves.
The victory stretched Brendan Rodgers' unbeaten record against Rangers to 12 games since arriving at Parkhead in 2016 as Celtic moved into second place, three points behind Hearts, while Gerrard's side have five points from 12 and sit in seventh position.
Goldson (25), who signed for the Ibrox club in the summer, said: "This is the first time I have played in a derby but I have just said that when I came here in pre-season I heard a lot of people say how much better they were, how they beat Rangers 5-0 last season.
"I thought they were going to be like Barcelona.
"There was such a down in our club of how big the gap was, it was like some of our players, that are maybe not here any more, were looking at them like they were nowhere near catchable.
"I'm not going to say they are not a good team.
"They are a good team and we respect them. But we are getting closer and the players the manager has brought in have been together for two months. We will get closer."
But Bhoys skipper Scott Brown insists Celtic have a firm grip of the fixture and is confident about the Scottish Premiership title staying at Parkhead.
He said: "We have got quality all over the park.
"We believe if we turn up we can beat anyone, especially at Celtic Park. We've beaten them here and at Ibrox.
"It is about what we do. It's not about Rangers."