The 20-year-old striker raised some eyebrows in the summer when he moved to the Glasgow club from Fulham on a four-year deal when he had options elsewhere.
The Frenchman scored a late winner against Astana to help the Hoops into the Champions League play-off - from where they qualified for the group stage into a pool featuring Barcelona and Manchester City - but he would not have been playing against Rangers if Leigh Griffiths had recovered from a hamstring injury.
However, in the first Ladbrokes Premiership clash between the two clubs in four years at Celtic Park and in Dembele's first Old Firm game, he scored the treble by a Celtic player against Rangers in the league since Stevie Chalmers in 1966.
Further goals from Scott Sinclair and substitute Stuart Armstrong piled on the misery for the visitors whose scant consolation came through striker Joe Garner's goal.
Rodgers, who confirmed that Griffiths is also out for the Champions League game away to Barcelona on Tuesday night said: "I think first of all I have to congratulate Moussa's agent
"When we heard he was available, I spoke to a number of people who know him.
"I thought there was a possibility to get him, I still felt it was probably a long shot purely because of his age, (he is) a sought-after striker with top teams in the Premier League wanting him.
"From the first day I met his agent, he was very clear that he is not in a rush.
"He knows he is an outstanding young talent but at 19 (when the deal was done) he knew he had to go to a club who could maybe develop that talent, make him a winner and if he does leave then he leaves the club being a winner and having improved his footballing ability and still being very young.
"Normally that doesn't happen
Some will follow the money and believe you me he could have got a lot more money than what he has got here.
"But his attitude is refreshing, he is a lovely boy to work with, he wants to improve.
"You see the power of the header at the first goal, for the second you see the speed he has and the skill to beat the defender to finish and the third one is a wonderful touch and finish with the left foot.
"So he is a big talent, he is still very young with a bit of work to do but it is really pleasing for him to get a hat-trick on a special occasion like that."
Dembele confirmed his desire to improve his game at Celtic and insists he will be ready for the Nou Camp.
He said: "I could have gone to other clubs but I wasn't thinking about money, I was thinking about the football first and to get more experience at a young age.
"We are playing in the Champions League and for a 20-year-old it is something huge and it gives me more and more experience.
"When the manager needs me I am here and I showed what I am all about.
"It is good for the team
We are a good group and if someone is not here, someone else who replaces him is ready.
"If I have to start (in Spain) I will be ready like I am every game.
"As a player you need to be ready for every challenge."
Midfielder Scott Brown is one player who may not start, or even feature at all, at the Nou Camp after Rodgers revealed he had suffered a knock in the Old Firm derby
Source : PA
Source: PA