Wales showed spirit to stay in the contest against Argentina and were hunting a pair of bonus points with the clock in the red.
But the Pumas were convincing winners when responding to an opening round defeat by Scotland.
“We were just slightly off it around our physicality, first time tackles, speed around the ruck – the basics where you need to be at it at this level,” said Adams.
“We still managed to find ourselves in the Test match and it was going back and forth until they pulled away with a couple of scores before half-time.
“Argentina are a good team when they stay on top of you and if you are not at it in the areas that I have mentioned – and with your discipline – then teams will punish you.”
Wales face a South Africa side who have started the Nations Championship with victories against England and Scotland.
The Springboks demolished Tandy’s side 73-0 at Principality Stadium in November, when the hosts were stretched due to the fixture being outside of World Rugby’s window.
Wayne Pivac’s Wales won for the first time on South African soil in the second of three Tests in 2022, when Adams scored the crucial try. Four years on, being competitive would be considered a success in Durban.
Wales again have to spend almost a day travelling with a journey of more than 5,000 miles that crosses five time zones.
Adams has dismissed this issue after Scotland made the same trip and almost shocked the Springboks before losing 42-28.
“Every team has to travel,” said Adams.
“Scotland made the journey and they were in the Test for most of the game. So there’ll be no excuses.”