The most galling thing for Rangers is that a five point and 17 goal advantage as held over them by Celtic in the Scottish Premiership does not look at all inappropriate. Ange Postecoglou’s team mauled their city rivals in the season’s first Old Firm game.

No wonder, then, that the Australian offered a post-match battle cry in respect of Tuesday’s Champions League visit of Real Madrid to Glasgow. “Let’s go down swinging,” said Postecoglou. Celtic, so high on confidence, will not alter approach against illustrious opposition.

Related: Celtic 4-0 Rangers: Scottish Premiership – live!

Celtic’s preparation for a clash with the European champions could hardly have been better. They have cracked home 17 goals in three games. That lead over Rangers, even so early in the season, already looks unassailable. Not that Postecoglou subscribes to that particular train of thought.

“The league table is not important,” he said. “What is important is how we play. If we keep playing like that, we will be hard to stop. But five points does not get you anything right now.”

What Celtic will receive, and rightly, are plaudits. They swaggered to victory without their star striker, Kyogo Furuhashi, after the Japanese suffered a shoulder injury inside five minutes. Postecoglou stated it was too early to know whether Kyogo will recover in time to face Madrid.

Rangers could not handle the appetite, organisation and slickness of their hosts. Not that Giovanni van Bronckhorst’s shellshocked team did not play a part in their own downfall. Goal number one arrived after Rangers slept at a quick Jota thrown in. Following a Matt O’Riley flick to Liel Abada, the ball was in the net. Jon McLaughlin, the Rangers goalkeeper, should have done far better with Abada’s shot when on the spin.

Rangers did rally for a brief first half period. Antonio Colak should have equalised but instead failed to connect properly with a Borna Barisic cross.

Celtic duly showed their old foes the art of ruthlessness. Again, speed of thought was key. This time a quick free-kick left Rangers flat footed. O’Riley played in Jota, who dinked a wonderful finish over the advancing McLaughlin. Number three arrived before the break, Abada slamming through McLaughlin’s legs after reacting quickest to a loose ball.

Van Bronckhorst called upon Alfredo Morelos with half an hour to play as Rangers looked to even snatch consolation. Yet the Colombian striker, who was left out of Rangers’ squad for the recent Champions League tie at PSV Eindhoven because of concerns over his attitude, looks way short of match fitness. The Morelos issue is just one of umpteen facing Van Bronckhorst. McLaughlin lacks the presence and talent to be a first choice Rangers goalkeeper.

Ridvan Yilmaz, a left back signed amid much fanfare from Besiktas, is not deemed ready to start fixtures such as these. Barisic plays where Yilmaz was supposed to; the Croatian’s defence shortcomings were seized upon by Celtic. Van Bronckhorst has proven himself a highly capable manager in European competition but, in the Scottish top flight, Celtic have raced well ahead.

Celtic’s fourth goal summed up a horrid Rangers afternoon. McLaughlin passed the ball straight to the substitute David Turnbull, who returned the ball with interest. A 4-0 victory pointed towards foregone conclusion in respect of this season’s championship.

Van Bronckhorst was left searching for answers. “There are still a lot of games to be played, plus three games against Celtic,” said the Dutchman. “We have to move on and get stronger and make sure the moments we had today can never happen again, no matter who we play. Everyone needs to reflect in what they did well and what they
did wrong, same for me.”