Fourth seed Devendro, who got an opening round bye, defeated Argentina's Leandro Blanc 3-0 in a lop-sided contest, while former Commonwealth Games gold-medallist Manoj upstaged second seed Mohamed Eslam Ahmed Aly of Egypt with a dominant 3-0 show.
Devendro, also an Asian silver-medallist, will be up against South Africa's Sibusiso Bandla, who defeated Korea's Lee Yechan in his prequarter-final bout, on Tuesday.
The 23-year-old Indian has to make the final to book a berth at the Olympic Games.
"Devendro used his right straights and left hook punches in brilliant combination. His uppercut was also very good and precise. In the second round, he somehow twisted his foot but managed to handle the situation on his own. He was brilliant in all three rounds and won the bout unanimously," national coach Gurbax Singh Sandhu said.
Manoj will take on Bulgaria's Ayrin Smetov Ismetov on Tuesday in his pre-quarter-final bout after upstaging a more fancied opponent.
The former Asian bronze-medallist will be assured of an Olympic spot if he makes the semi-finals in the ongoing event.
"Manoj put up a superb show, one of the best of his career. He was very sensible, I have never seen him this calm and measured in his approach. He kept his opponent at long range, totally avoided close contact with Mohamed," Sandhu said.
The tournament has 39 qualifying spots up for grabs -- two in the 49kg category, five each in 52kg, 56kg, 60kg, 64kg, 69kg, 75kg and 81kg, and one each in 91kg and +91kg.
Over 400 boxers from more than 100 countries are vying for these slots
in the final qualifying tournament for amateur boxers.
India haven’t sent any entry in the 56kg category as Shiva Thapa had already qualified for the Games during the Asian qualifiers in March.
Image: Devendro Singh
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