Sachin out-punched France's Enzo Grau 3-0 to sail into the last-four stage.
However, it was curtains for Naveen Boora (57kg) and Sandeep Ghanghas (75kg), who bowed out after quarterfinal losses.
While Naveen lost 0-3 to American Gabriel Flores, Sandeep was outwitted by a similar margin in his bout against Romanian Alberto Biro.
India had not won a single medal at the previous edition of the event in 2013, a massive fall in performance given that it was an Indian -- Vipin Kumar (50kg) -- who was adjudged the best boxer in the inaugural championship back in 2007.
In 2009, India had returned with one silver and three bronze medals, followed by a silver and a bronze in the 2011 edition.
