Playing in Australia, Brazil struggled to create consistent attacking pressure and were repeatedly exposed defensively. Nestory Irankunda put the hosts ahead with a superb free-kick before Bournemouth forward Rayan rescued Brazil with a stoppage-time header.
Australia looked the more organised side during much of the match and created several opportunities as Brazil struggled to maintain their defensive shape.
Brazil thought they had taken the lead in the first half when Estevao finished after combining with Endrick. However, VAR ruled out the goal after identifying a foul by Bruno Guimaraes earlier in the move.
The visitors improved after the break and enjoyed more possession, but clear chances remained limited. Raphinha and Estevao came closest before Ancelotti introduced Samuel Lino, Pedro and Rayan in an attempt to change the attack.
Australia eventually found the breakthrough through Irankunda, whose free-kick gave the hosts a deserved lead.
Brazil increased the pressure after falling behind as Australia dropped deeper to protect their advantage.
The breakthrough finally arrived with virtually the last action of the match. Rayan rose to meet a corner and directed his header into the net to secure a draw.
The result spared Brazil from defeat but did little to resolve concerns about their overall performance.
Only four players from the team that started Brazil's World Cup defeat to Norway began this match, although the lineup still included experienced figures such as Marquinhos, Guimaraes, VinÃcius Junior and Raphinha.
The performance leaves Ancelotti with plenty to address. Brazil's defence lacked consistency, while their attacking players struggled to produce the individual quality expected of them.
VinÃcius had limited influence, while Endrick was substituted in the second half without making a significant impact. Raphinha provided some of Brazil's more promising moments, but the team lacked a sustained attacking threat.
The draw also adds to the scrutiny surrounding Ancelotti's attempt to establish a settled identity for Brazil. The Italian's task is complicated by the expectations attached to one of international football's most successful teams.
Brazil will have another opportunity to assess their progress when they face Australia again on Tuesday before continuing their schedule with a match against India.