Brendan Rodgers may bemoan the luck of the draw. On the evidence of a harrowing evening for Celtic, facing a Paris Saint-Germain side determined to send a statement of intent to open the Champions League would always have been an insurmountable challenge.

Some context for Rodgers and Celtic will arrive with what PSG do next. Celtic, though, need to banish this French canter from their minds in preparation for what has always looked a pivotal Group B fixture at Anderlecht in a fortnight.

European football’s haves brutally exposed the have nots to the point where the win was secured by half-time. This matched the heaviest home defeat in Celtic’s 129-year history; Heart of Midlothian won 5-0 here in 1895. The intervening years surely have not witnessed mismatches such as this.

Rodgers was riled by his team’s first‑half showing. “We played like under-12s,” he said. “We were too passive, didn’t press well enough and stood off.

“I’m not worried about records. Tonight we were playing against world-class opponents but in the second half – it’s always easy to play at 0-3 – I want them to start like that.

“At this level you have to make the ball work and you have to have that belief. In that opening period, there was too much space, the physicality wasn’t what it should have been. Whoever we were playing, it wasn’t what we would like.”

PSG’s front three of Neymar, Edinson Cavani and Kylian Mbappé – anxious to announce themselves as collectively the best in Europe – helped themselves to goals. The final tally for the visitors just about explains an on- and off-field gulf. Too many of Celtic’s players did not perform to their capabilities – there were shortcomings in defence and the failure to retain possession elsewhere – but PSG’s play was a joy to behold. From their manager came a post-match warning to the rest of the Champions League.

“I am very happy but it is a mixture of happiness and calmness,” Unai Emery, said. “I am really confident that we can continue on this journey we have set out on. “

We know there will be more difficult times to come. This was a good step forward for those more difficult times.”

Celtic’s shortage of defensive options meant a start for the 18-year-old Anthony Ralston at right-back. For all this will inevitably lead to carping regarding the lack of talent depth for an environment such as this, for Celtic to field an academy product in such a marquee fixture is testament to Rodgers’s fresh thinking. A wider debate concerns whether he should have been afforded better options. With Jozo Simunovic Celtic’s only fit and orthodox centre-half, Mikael Lustig stepped inside to allow Ralston his start. In direct opposition to the teenager? Neymar. It can only get easier from here.

The harsh comment at the point of the opening goal would be to suggest Celtic did not heed a series of earlier warnings. Rodgers’s team had what looked a perfectly legitimate shout for a foul on Scott Sinclair as PSG stole midfield possession. As Celtic protested, PSG marauded forward. Adrien Rabiot found himself goal side of Ralston, with the midfielder feeding Neymar. The Brazilian, already a pantomime villain in these parts after spats of the recent past, only angered the Celtic support even more with his composed finish over the onrushing Gordon.

Celtic almost responded immediately by virtue of a weapon that Emery had identified before the match. Leigh Griffiths conjured up a wonderful free‑kick from more than 30 yards out, with Alphonse Areola leaping to supply a save of identical quality. It was to be Areola’s only meaningful action of the evening.

PSG doubled their lead with a goal that involved each of their celebrated front three but in wholly unorthodox style. Neymar was unselfish in heading Marco Verratti’s cross back towards Cavani, who promptly took a fresh air swipe at the ball. The No9 was spared ignominy by Mbappé, who arrived to clip home.

Cavani notched No3 from the penalty spot, five minutes before the break, after Simunovic pulled the same player’s shirt. PSG’s canter was all too much for one punter in a green scarf, who raced on to the pitch before trying to boot Mbappé. In summing up the Celtic night thus far, he missed after the Monaco loanee took a sidestep. The more serious element relates to inevitable Uefa intervention towards Celtic, a club who have had a series of fines in recent years because of the conduct of their supporters. “It was bitterly disappointing,” Rodgers said of the incident.

Celtic began the second half in bullish mood and still, unfazed, PSG defended as if barely troubled while attacking at will. In Rabiot, they had a performer arguably more impressive than the forwards who claim widespread attention.

Julian Draxler triggered panic in the Celtic goal area with a cross, Lustig’s deflection meaning goal No4. Cavani promptly headed in a fifth from an improbable angle. Celtic are seldom routed at home; it will be of little comfort that the instigators will do likewise to far better teams.