Sunibala faced a tough test in the repechage contest but she managed to prevail over Monika Burgess of Canada in a battle that lasted for three minutes and 58 seconds to make the medal round.
She will now fight for the bronze medal with Scotland's Sally Conway, later in the day.
However, it was curtains for Garima Choudhary in the women's 63kg category after she went down fighting in her repechage round.
Garima, who was the only Indian judoka to have qualified for the London Olympics in 2012, lost to K J Yeats-Brown of England in the repechage. Yeats-Brown won on the basis of two Wazaris.
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Earlier on the day, Garima got the better of Soctland's Sarah Clark in the quarterfinals, while she defeated Bibiene Fopa of Cameroon in just nine seconds in the round of 16.
While Balvinder went down to Mozambique's Edson Madeira, Vikender lost to E J Omgba Fouda of Cameroom.
Indian Judokas won two silvers and a bronze on the opening day.