Amidst the jubilation and glorious optimism that the Socceroos' opening World Cup qualifying win over Qatar provoked there was one sobering moment - the international retirement of Craig Moore.
And just how to replace the man that has been Australia's defensive rock over the past decade looms as the most immediate challenge for new Socceroos' boss Pim Verbeek.
Such was the quality of performance displayed by the Socceroos during their 3-0 win over the outgunned Qataris, fans could have almost been forgiven for asking 'Guus who' as the Australians showed they are just as capable of qualifying for the next World Cup under Verbeek as they were under his more famous countrymen Hiddink in 2006.
But all the plaudits that justifiably went Verbeek's way on Wednesday night in Melbourne, following his dream start as Australian coach, will soon disappear if Australia struggles against the other teams in Group A in Asian Cup winners Iraq and rising power China.
Remember Australia needs to finish in the top two in Group A to progress to the final and more difficult stage of qualifying when the ten remaining teams will be split into two groups of five - with only the top two in each group certain of reaching the next World Cup finals in South Africa in June, 2010.
And remember that the game against the 88th ranked Qatar at home was by far the easiest match in Australia's group with the next match to be played at high altitude in China on March 26 before a testing four games in 20 days in June - two of them in the fierce heat of the Middle East against Qatar and Iraq.
And all without the inspirational Moore, who pulled the pin on his international career following the 3-0 win over Qatar.
That was Moore's 39th cap in a career stretching back to 1995 - the highlight of which was his successful penalty during that memorable 2-2 draw with Croatia in Stuttgart, a result which took Australia through to the knockout stages of the World Cup for the first time.
It is not just Moore's calmness under pressure and on the ball at the back that Australia will miss but also his equally calming affect on his fellow defenders such as captain Lucas Neill and our much-improved left-back David Carney.
Now the search is on for a replacement and if you look at the 39-man squad that Verbeek named for his first game in charge, there are not a lot of stand-out options right now.
German-based Michael Beauchamp appears the logical choice after he performed well when given his opportunity at last year's Asian Cup.
But despite being 26, Beauchamp is still relatively inexperienced - having played for Australia on just 11 occasions while he is still yet to establish himself at club level in Europe where he is now playing for Nurnberg.
And after Beauchamp, the options are even more limited.
The other European-based defender called up by Verbeek in Michael Thwaite was the only overseas-based player not called up into the final 18 man squad for the game against Qatar - not a good sign as to his international prospects under the tough-talking Dutchman.
And that only leaves A-League players ranging from Melbourne Victory veteran Kevin Muscat, who is even older than Moore, to experienced local-based players such as Roddy Vargas and Jade North to promising youngsters such as Sydney's Mark Milligan and Perth's Nikolai Topor-Stanley, who is more a left-back.
It looms as a challenging task for Verbeek but a great opportunity for one of the A-League players to step up to international level.
But one thing is for sure, the retirement of Moore leaves a hole in the Australian line-up that is unlikely to be filled in the short-term.
However the problem for the Socceroos is time on their not side when it comes to finding another reliable international-standard centre-back.