I was impressed by Tspiras and Varoufakis intellectual skills if unsure about their negotiating prowess

I beg to disagree. It was guerilla warfare and the way Varoufakis used the press was brilliant. A thousand ambushes where you kill two at a time and the run away. You can't afford to lose two as well. To others it seems like tou retreated, hence a loss, when in fact over the long run attrition takes a bigger toll on the other side.
On the other hand, Tsipras stayed in the shadows and lo and behold, a 40yr old untested politician gained statesman status in the eyes of his people and many others.