Djed Spence, Brennan Johnson, Mikey Moore and Will Lankshear all made the net ripple for Tottenham, who were without seven international representatives in Rodrigo Bentancur, Cristian Romero, Giovani Lo Celso, Guglielmo Vicario, Micky van de Ven, Radu Dragusin and Pierre-Emile Hojbjerg.
Left-backs Ben Davies and Destiny Udogie also missed the clash with the injuries they picked up towards the end of last season, while Richarlison was not involved either amid concerns over his fitness levels.
Despite the brilliant second-half displays of some of Postecoglou's young stars, the Spurs boss may opt to stick with a largely similar formula from the first whistle, as none of his players completed over 45 minutes at Tynecastle Park.
New signing Archie Gray would therefore continue as a centre-back alongside Brandon Austin, Pedro Porro and Jamie Donley in defence, although there might be scope for Ashley Phillips to come in for Oliver Skipp.
The same can be said of Lucas Bergvall in midfield, as the Swedish sensation seeks to partner Yves Bissouma, in turn forcing James Maddison slightly higher up the field.
The ex-Leicester City man's position change could spell bad news for Johnson, in spite of his opener on Wednesday, as Dejan Kulusevski, Timo Werner and Son Heung-min look to reprise their attacking roles.
Tottenham Hotspur possible starting lineup:
Austin; Porro, Gray, Phillips, Donley; Bissouma, Bergvall; Kulusevski, Maddison, Werner; Son