While ONGC thrashed Army Red 4-1, Indian Navy got the better of Air India 2-0 at the Ambedkar Stadium.
Asim Hasan (39th and 58th minute), Henry Ezeh (65th) and Parvinder Singh (76th) found the net for ONGC, before Vipin T V scored what turned out to be the consolation goal for Army Red in the 19th minute.
Riyad B and (75th) and Raman Rai (77th) scored for Indian Navy.
Star-studded Mohammedan Sporting will be playing in the Durand Cup for the first time since 2006.
The winners of the group qualify for the semifinals.
Mohammedan Sporting, which last entered the Durand final in 1992, are a formidable squad this season and have several star players like Australian striker Tolgay Ozbey, Nigerian attacking midfielder Penn Orji and Brazilian defender Luciano Sabrosa and several good Indian players also.