Khan scored off a 14th minute penalty corner to open the scoring. He increased the lead with a field goal in the 28th minute.
Khan recorded the first hat-trick of the tournament when he converted a penalty corner in the 36th minute to ensure that BPCL held a 3-0 lead going into the break.
Striker Jarnail Singh completed the rout with a last-minute goal.
In the other two matches of the day, a star-studded Air India line-up thrashed Integral Coach factory 7-1 while former champions, Indian Railways defeated All India Customs and Central excise by a solitary goal scored by Gagandeep Singh.