Probably it was a mistake to bat first in all three matches after winning the tosses! I was hoping South Africa to win a toss (in the last match at least) and see what they do! Sri Lanka beat South Africa in a series where they batted last! What I observed was Indian bowlers tried too hard in the last innings to pick wickets in order to defend small totals... But whenever they bowled normally without trying hard, they succeeded.
India won matches overseas lately due to freakish batting performances (like Shami, Bumrah, Thakur scoring runs when not expected) Once this didn't happen (SA bowlers were smart to identify this and made sure it didn't happen) the issues in the middle order got exposed and this is the main reason for the loss! Al

so we missed Rohit, though he would faced problems with the lateral movement, but he is improved now and would have done much better than Agarwal (Actually Agarwal is better batting at No.3 or 5)