While Manoj defeated Nepal's Deepak Shrestha 3-0, Madan Lal (52kg) got the better of Iraq's Murtadha Al-Sudani by the same margin.
Madan started the proceedings for India and gave the contingent a perfect start by defeating Al-Sudani 3-0 in a bout marred by excessive clinching and holding.
The two pugilists fought out a rather unattractive contest, which lacked spark.
However, the Indian stood out for exploiting his rival's weak defence quite easily in all three rounds. Madan was clearly the better of the two in ring-craft, thwarting Al-Sudani's feeble attacks with consummate ease.
Next man in for India today was Manoj and the two-time bronze-winner at the Championships hardly broke a sweat against his seemingly low-on-confidence opponent.
The former Commonwealth Games gold-medallist dictated the pace of the bout and relied mostly on his left hooks and uppercuts to do the scoring. Deepak spent most of the time trying to evade the Indian and hardly manage to connect the few attempts at hitting Manoj.
The third round followed a similar pattern before Manoj eased into the next level.
The Haryana-lad also has a tough contest next up -- a face off against second-seeded Kazakh Samat Bashenov. Bashenov got the better of Uzbekistan's Fazliddin Gaibnazarov 3-0.
With this the number of Indians in the quarterfinals stands at seven.
L Devendro Singh (49kg), Shiva Thapa (56kg), Vikas Krishan (75kg), Manpreet Singh (+91kg) and Satish Kumar (91kg) have already booked their last-eight stage berths.
The event is a qualifier for the October World Championships in Doha -- the first qualifying tournament for next year's Olympics in Rio de Janeiro.
