In-form striker Leigh Griffiths took his tally for the season to 16 with a double, one from the penalty spot.
Midfielder James Forrest scored the third to leave Adam Rooney's late header a consolation as the leaders opened up a seven-point gap over the Dons, who have failed to win any of their last five league games.
The Norwegian, who revealed skipper Scott Brown will miss the home Europa League game against Molde on Thursday with a knee injury which kept him out again, praised his side for their display in the midst of a congested fixture list which included a tough Scottish League Cup quarter-final win over Hearts at Tynecastle in midweek.
Deila said: "I'm very happy and proud because it has been four games in nine days and it was a very good 90 minutes where we should have scored more.
"They had rested and prepared for a week and it was a better chance for them to get something.
"But we showed that we were the best team and now we are seven points clear of Aberdeen and that is very good as we go into November."
Deila's praise of Griffiths, who opened the scoring with a fine header just before the interval, was a bit more qualified.
He said: "He is getting more and more mature
He still can lose concentration a little bit but he smells danger all the time, he sees when things are happening and he is a great finisher.
"The only thing I was angry with today is that he didn't play in Stuart Armstrong, instead shooting himself from 19 yards.
"Apart from that, the first goal was high class and the cross from Kieran Tierney was very nice as well."
Brown had to withdraw from the Hearts match in midweek after picking up the injury in the warm-up.
However, Deila, hoping that defender Jozo Simunovic's substitution was only down to cramp, is happy with the cover he has in midfield for the Scotland captain.
Asked if Brown would make the Molde game, Deila replied: "No I don't think so
But the injury is not major so there is a very good possibility that he is back after the international break
"You always want Scott Brown in your team but we have players who can do a job here.
"Stefan Johansen is one of the best midfielders for Norway and you have Nir Bitton who plays for Israel, so I have a good group of players.
"Jozo hasn't played so many games and has played three games in nine days, so we hope it is only cramp and he will be ready for Thursday."
Aberdeen boss Derek McInnes claimed it would be disrespectful to the rest of the league and not just the Dons to believe the title race is over.
He said: "Only someone really foolish who doesn't know what they are talking about would say at the minute that anybody else but Celtic will win the league.
"But I think it is wrong to say it is over and think it is disrespectful to the rest of the teams, not just ourselves, to think that a league can be won in October.
"I think there was a similar points difference last season and everyone said the same thing and when we met again there was still something on the game.
"We have to manage our own game and own position
Our fight has never been with Celtic, our fight is with ourselves, to improve, and nothing changes.
"I still believe in the last two performances that we have been more like ourselves and will be looking to build on that against Dundee United next week and hopefully get back to winning ways."
Source : PA
Source: PA