Barry John slammed Wales for a "clueless" display in their 26-12 defeat to Argentina.
And the Wales and Lions legend says he fears the worst in forthcoming internationals against New Zealand and Australia.
"Wales played clueless rugby throughout. They were so easy to read and there was no attacking threat at all," wrote former fly-half John.
"While Wales were woeful, there needs to be some credit given to Argentina, who I have so much respect for now after watching them.
"The mind boggles at the thought of what the Wallabies and All Blacks will do to Wales if they perform like that again".
More immediately, Wales face Samoa on Friday with the Pacific Islanders thirsting for revenge after a narrow World Cup defeat by the Welsh last year.
"We always assumed the (Wales) team on Friday night would be slightly different and give some of the fringe players a chance," said John.
"But because of the injuries and poor performances they might decide they can't do that and stick with the players who played so poorly yesterday.
"Based on what they have seen from Wales, Samoa will fancy their chances."