I like Pochettino, but this whole argument that someone needs to be a proven winner with certain a pedigree and history is stupid. It's also the same logic that got us Mourinho.
For instance, Guardiola took over the Barcelona first team after 1 season with the reserves (where he won their league). If you applied the same logic then as some of our fans do, Guardiola never would have got this promotion. He never would have managed one of the best sides on earth. And I don't think he ever would have made it.
With that said, the same people parroting this argument need to do some reading. Ole has won the league with United reserves, as well as the Norwegian league twice... Pochettino has never won a thing.