Dreams of Asian Champions League success received a wake-up call for the Brisbane Roar after they were downed 2-0 by FC Tokyo in their opener at a wet Suncorp Stadium on Tuesday night.
After earning comparisons with Barcelona, the Roar made it clear they wanted to rub shoulders with the real article in December's elite Club World Cup by winning the ACL on debut.
But Brisbane won't be having it all their own way after a faster, crisper and more clinical FC Tokyo made light of soggy conditions to get home through Yazawa Tatsuya (46th minute goal) and Hasegawa Ariajasuru (55th).
On paper the all-conquering A-League champions lined up against a side that had only recently earned promotion to Japan's top league.
And the Japanese outfit had only arrived in Brisbane on Monday morning minus their captain Yohei Kajiyama and Brazilian spearhead Lucas after they were injured in last weekend's 2-1 Japanese Super Cup loss to Kashiwa Reysol.
But FC Tokyo - who earned ACL qualification by winning Japan's Emperor's Cup - looked a class above a Roar outfit that appeared starstruck.
Only Adelaide United - which lost the 2008 final to Gamba Osaka - and Newcastle Jets have progressed past the group stages.
And Roar will do well to add to that list after their attacking style that at one stage earned a record 36-game unbeaten A-League run failed to make a dent on fellow ACL debutants.
The Roar slowly began working their way into the game and must have thought they had done enough to go into the break with a clean sheet before Yazawa struck in first half injury time.
Brisbane again gifted FC Tokyo possession before Yazawa capitalised on Tokunaga Yuhei's sublime pass - and poor defence from Mohamed Adnan - to break Roar hearts.
The killer blow came in the 55th minute when Hanyu Naotake beat the off-side trap and Theoklitos bunted away his attempt, only for Hasegawa to put away the ricochet.
The Roar's next two ACL games are away - Beijing Guoan on March 20 and South Korea's Ulsan Hyundai on April 4.
Asked how the Roar could bounce back in the ACL, Postecoglou said: "Play more like ourselves.
"This is not something you can walk into and feel comfortable straight away - you need time to find your feet.
"Our pressure wasn't as it should have been. We looked a bit nervous.
"But this will be good for us. It is an experience that will put us in good stead.
"We have five games to go. I feel we will get better and better as we go along."
FC Tokyo coach Ranko Popovic seemed pleasantly surprised by the standard shown by his side, which is still in their pre-season.
"I am proud of my guys and I think the whole of Japan should be proud - they played very smart," he said.
"Without a good opposition it is impossible to play a good game - but we were a little bit better."
More than 12,000 braved the miserable conditions.