IT was the night of the great flood in Champions League group C. Showers of biblical proportions battering Manchester meant Pep Guardiola’s City would have to wait before they could get their European campaign under way against Borussia Monchengladbach. Eight hundred and fifty nine miles away, a deluge of even greater magnitude was relentlessly crashing against a Celtic side that simply couldn’t keep their heads above water.

The Scottish champions were never expected to get anything from this game. Even after the 5-1 rout of Rangers, coupled with Barcelona’s shock defeat at home to Alaves, few would have been surprised as the goals rained down in the Nou Camp.

The devil as always was in the detail. During that loss to the La Liga new boys at the weekend, Barcelona manager Luis Enrique chose to make eight changes ahead of this match against Celtic. Most notably, out of the ‘trident’ front three of Luis Suarez, Lionel Messi and Neymar, the latter was the only one who started that match.

Read more: Rodgers refuses to come down hard on players after worst European loss in club's history

The reunion with his two forward team-mates, for the first time this season, was cataclysmic. Of the seven goals that flew into Dorus De Vries’ net, the trio had seven assists and six goals.

There aren’t enough column inches to pick apart and praise the part played by the three in each goal, just as it would be unfair to lambast a shattered Celtic team who were simply outclassed. Having said that, it took just three minutes for them to come together. A perfectly-weighted Neymar pass found Messi and with one swift turn and a ferocious strike blasted Barcelona on the way to an emphatic win that would be Celtic’s heaviest defeat in European competition.

One Hoops fan commented on Twitter at full-time if Messi wasn’t playing his team may have just lost by four. In truth, if he wasn’t playing they may have had a draw. The best player in the world grabbed a hat-trick but that was only a part of the masterclass on display at the Nou Camp. Sitting primarily out on the right, he constantly drifted in, often coming deep, dictating play and changing up the pace with a stunning range of sharp passes.

Read more: Rodgers refuses to come down hard on players after worst European loss in club's history

Even with a back five, Celtic were easily picked apart and carved open by the Argentinian. Concern hung over the 29-year-old prior to kick off that he’d not be fit enough to last 90 minutes. It is a measure of the swagger and ruthlessness of Enrique’s team that even with a comfortable lead Messi stayed on to the death until the torture was finally brought to a stop by Ovidiu Hategan.

As scary as this may sound, it easily could have been more. Barcelona always looked like stepping up a gear. Fifteen shots peppered the Celtic goal to the four at the other end, while the 858 passes – 766 of which were completed – simply dwarfed anything the Parkhead club could come up with – 332 and 263 respectively.

This was a statement of intent from Barcelona, make no mistake about that. Watching rivals Real Madrid lift the Champions League trophy last season will have cut deep for a club that, despite that fact, are still regarded as the biggest and finest club in the world. On the evidence of this 7-0 thrashing, it’s hard to argue.

Of course their European credentials should not and will not be measured against a Celtic team who at times shot themselves in the foot in Catalunya. You never know, if Moussa Dembele hadn’t missed his penalty it may have just been 7-1.

Read more: Rodgers refuses to come down hard on players after worst European loss in club's history

Regardless, the torrent witnessed here, and the three forces of nature that stirred it up, provide an ominous forecast of things to come.