Both Shyam and Rohit are medallists from the 2015 edition of the event. While Shyam had won the gold medal, Rohit had clinched a bronze.
The two boxers had won silver medals at the Senior Nationals in Guwahati last year.
Shyam got the better of Thailand's Samak Saehan. Rohit, on the other hand, defeated Kazakhstan's Kuatov Kuan.
However, it was curtains for former Commonwealth Games gold-medallist Manoj Kumar, who lost in the welterweight quarterfinals.
Shyam and Rohit have tough bouts up next in the semifinals tomorrow.
While Shyam will square off against Cuba's Jorge Alejandro Grina Mer, Rohit will be up against Uzbekistan's Abduraimov Elnur.