Wallabies head coach Michael Cheika insisted Australia should have been able to see off Scotland, despite Sekope Kepu's red card.
Kepu was sent off as hosts Scotland ran riot at Murrayfield on Saturday, embarrassing the Wallabies 53-24.
A moment of madness from Kepu proved costly for Australia, who led 12-10 at the time of the lock's dismissal following a shoulder into the head of Hamish Watson in the 39th minute.
Scotland capitalised on their numerical advantage but Australia boss Cheika refused to use it as an excuse after the Wallabies' European tour ended in horror fashion.
"I thought we still could have won with 14, to be honest," Cheika said. "We came back and started off the second half very well.
"We just had to keep believing in what we wanted to do and instead we didn't. We threw away the ball.
"We had less players and if you throw away the ball that is sort of what is going to happen. It's definitely unfortunate but definitely not the red card - that happens in matches.
"I don't think it was a turning point."
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It was not the farewell Stephen Moore had hoped for as the 129-cap star made his final appearance.
Speaking about Moore, a veteran of three Rugby World Cups and Australia's second-most capped player behind George Gregan, Cheika added: "I don't think a player's career is summarised by one match, any match or a moment in the game.
"His attitude and character will be imprinted on this squad going forward. I've been lucky to have him involved from 2015 and beyond.
"Considering our situations over the last few years he has been an outstanding help to me. We've had a lot of battles, on and off the field, and he's kept the team up and hungry all the time."