The first round both were better which is why it was TIE according to Hansika. I think Sadhna lost her confidence during the tie breaker round because she had to choose between her sister and husband. This particular dilemma wasn't before here when she signed in for competition. She simply couldn't give her best thinking that she was competition against her jiji.
Honestly I wouldn't appreciate if Sadhna won this competition. No matter how much you try or whoever the genius is who had trained you, a non dancer cannot compete with professional dancers on the basis of 4 days practice. Its not singing or reciting poems, it's dancing and it's not about just twisting your body this way or that way on bollywood numbers. I agree Sadhna should have been the winner but it would have been unrealistic.
Now I hope Sadhna/Ranvir finds out the truth of Kausi's condition or even better if one of them overhears Guruma and Sadhna's conversations about why she danced in the first place.