Nitin Kumar gave Indian Oil the lead in the 10th minute but the local team kept the rival forwards at bay with some resolute defence to keep 1-0 at half-time.
In the second half, IOC scored thrice through former international V R Raghunath (50th minute) through a penalty corner conversion, Roshan Minz (55th) and Gurjinder Singh (62nd) to secure a comfortable win.
Punjab & Sind Bank, which led 1-0 at half-time put it across the Navy team 4-2 thanks to a brace from Jaskaran Singh. Gaganpreet Singh and Parvinder Singh were the other scorers for the bankmen.
For Navy, the goals came through Rana Pratap (37th minute) and Ranjot Singh (47th minute).
ONGC which was held to a 3-3 draw by the Central Secretariat team yesterday, went on the attack against Mumbai HC from the onset and went ahead in the 17th minute through Shilanand Lakra.
Gurjant Singh put the reigning champions ahead 2-nil by putting one past the Mumbai custodian in the 26th minute.
ONGC added two more to the tally, by scoring in the 38th and 70th minutes through Neelam Xess and Jagwant Singh respectively.
Results : Pool 'A': ONGC bt Mumbai Hockey Association 4-0.
Pool 'B': IOC bt Chennai Hockey Association 4-0, Punjab & Sind Bank bt Indian Nacy 4-2.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)