THIS time the only thing tied in knots was the Linfield team.

Had it not been for some shocking finishing by the Scottish champions in the first-half, which could be put down to understandable rustiness, then double figures might have achievable. In the end, their wastefulness mattered little.

Unlike at Windsor Park there was no scarf scandal and nothing was used for target practice apart from the Northern Irish team’s goal. This was ridiculously comfortable for these Invincibles who negotiated this tie without much bother.

Read more: Brendan Rodgers wants to attack Rosenborg - but banners and songs might come back to hurt Celtic and Linfield

Of course, this is what you would expect a strong Celtic to do against part-time opposition but the team from Belfast were a disappointment. They offered little apart from hope that the defeat wouldn’t be so terrible.

Therefore, it is difficult to judge where Celtic are right now given they were up against such a mediocre team; however, Brendan Rodgers seems to have his players at a pretty good level in terms of sharpness. It bodes well for what is to come next.

And that will be Rosenborg of Norway who got through to the third qualifying round of the Champions League after extra-time against Dundalk. They will be at Celtic Park next Wednesday.

The atmosphere inside the stadium wasn’t exactly cordial. Not all the fans “focussed on the football” which was the pre-match plea from the police. Linfield manager David Healy is right. There will never be a friendly between these two. Although if they did meet again then the makers and sellers of Irish and British flags is onto a fortune.

Read more: Brendan Rodgers wants to attack Rosenborg - but banners and songs might come back to hurt Celtic and Linfield

Rodgers went with, I think, a 3-1-2-3-1 with new signing Olivier Ntcham in central midfield and Moussa Dembele up top in place of last week’s pantomime villain Leigh Griffiths who was injured. Stuart Armstrong, who has yet to agree a new deal, was on the bench. Was it tactical or Rodgers making a point? Perhaps a bit of both.

The system and personnel mattered little if truth be told. Celtic were in control from start to finish.

Only four minutes - and a lot of Celtic passing - had taken place when Ntcham had shot from an angle outside of the box, the ball took a deflection and with Linfield goalkeeper Roy Carroll already on the ground having committed to the save, Scott Sinclair squeezed his effort in at the near post.

It was then a clear case of how many Celtic would score. Four was the answer.

Carroll continued his fine form from Friday by getting both hands to a bullet of a header from Dembele on 19 minutes courtesy of a Sinclair corner. Then Sinclair had a goal-bound shot put over off the head of Linfield’s own giant Mark Stafford. From that corner Dembele sent his header wide from close range.

Tom Rogic was next to go close with a low shot which fizzed along the ground and wide on 27 minutes, as Celtic continued to press. Indeed, the only real reason a second hadn’t been taken was that Celtic players kept getting in each other’s way in a bid to get on the scoresheet.

Celtic kept attacking and missing. Sinclair bent a shot wide at the end of a lovely break started by Brown. Worse to come when Dembele beat the offside trap, got clean through on Carroll and still couldn’t hit the target.

Read more: Brendan Rodgers wants to attack Rosenborg - but banners and songs might come back to hurt Celtic and Linfield

It was an odd evening at this stage. Celtic’s job was done, Linfield worked hard but were unable to affect the game’s flow and yet it remained 1-0. That was to change 90 seconds after the break.

This could be a special season for Rogic. The Australian is a real talent and a lovely player to watch. Not that Linfield would agree with that, as they could do nothing about his perfect shot from distance which he directed into Carroll’s bottom corner.

It then got quite nasty inside the stadium for a bit.

Why the Celtic fans in the standing section felt the need to bring out banners which weren’t even subtle references to the Troubles – one had a picture of Rodgers who I’m sure would want nothing to do it - only they can say.

The Linfield support did not take kindly to it – their own songbook was emptied including horrible child abuse stuff- and the police and stewards did well to keep the peace. It does make you wonder what a stranger to such things would make of it all.

UEFA might have something to say about such nonsense.

While all this was going on, Celtic passed their way through the Linfield defence and Sinclair’s cool finish into the roof of net on 54 minutes made it 3-0.

Read more: Brendan Rodgers wants to attack Rosenborg - but banners and songs might come back to hurt Celtic and Linfield

Sinclair was terrific. Only an equally impressive Carroll save denied him a hat-trick after an hour. The Englishman takes some stopping when he cuts in from the left.

Jonny Hayes got on and was denied a goal by the excellent Carroll whose save from the Irishman’s free-kick might have been the pick of the two dozen he made over the two legs.

And right at the end, Armstrong got a fourth as Linfield by now were out on their feet.

Celtic’s next challenge will be different and more difficult but it’s hard to see them not going through. On the pitch at least, Rodgers’s side are going along nicely.