The Indians, who were through to the semifinals even before today's match, led 5-1 at the breather and pumped in four more goals in the second session to stamp their authority over their lowly opponents.
Rupinder (4th, 19th, 27th, 61st minutes) scored four goals in the match, out of which three came via penalty corner, while Raghunath (29th, 52nd, 59th) converted short corners to emerge as the joint top-scorer of the tournament with Jang Jong Hyun of South Korea on six goals apiece.
Nikkin Thimmaiah (25th) and Malak Singh (47th) were the other goal-getters for India. Bangladesh's lone goal came from the stick of their skipper Md Mamunur Rahman Chayan (35th minute).
By virtue of this win, the Indians finished on top of Pool B with nine points from three games. Defending champions South Korea are second in this pool with six points. India will now face Pool A runners-up and hosts Malaysia in the second semifinal on Friday, while South Korea will be up against Pool A toppers Pakistan.
The match between India and Bangladesh started nearly 40 minutes late as the first game of the day between Korea and Oman was delayed due to heavy downpour in the evening. Playing under persistent drizzle and damp conditions, the Indians meant business from the beginning.
Such was their dominance that they earned as many as 10 penalty corners in the match, out of which they utilise six. The Indians were under no pressure as they played free-flowing hockey to put the Bangladeshi defence under constant pressure.
For the sparse crowd present at the Sultan Azlan Shah Stadium, there was excitement from the very beginning as it rained goals in the match. Ranked 31st in the world, Bangladesh were expected to be a mismatch for the eight-time Olympic champions India, and they turned out to be exactly that.
As their interim coach Roelant Oltmans indicated after the Korea match, the Indians went for attack against Bangladesh from the opening whistle. It took the Indians just four minutes to take the lead when Rupinder converted his side's first penalty corner.
India earned two more penalty corners soon after but the Bangladeshi defence stood tall to avert the dangers. But India doubled their lead in the 19th minute from their fourth penalty corner which Rupinder converted with a powerful high flick to the top left of the Bangladeshi goal.
Young Nikkin Thimmaiah then extended India's lead by scoring his first international goal in the 25th minute with a reverse shot from the top of the opposition circle. India soon made it 5-0 via a penalty stroke which they earned after Rupinder's flick from a penalty corner hit the body of a Bangladeshi defender.
Lanky Rupinder stepped up to take the shot from the spot and converted it successfully to complete his hat-trick. Bangladesh, however, pulled one back just at the stroke of halftime through captain Md Mamunur Rahman Chayan who converted their only penalty corner of the match to register their first goal of the tournament.
The Indians continued in the same vein after the change of ends and pumped in four more goals to assert their supremacy in the lop-sided contest. The Indians took a little while to get on the scoring mode in the second half with Malak finding the opposition net in the 47th minute. Thereafter, it was all a Rupinder and Ragunath show.
While Raghunath converted two more short corners in the second half, Rupinder matched his compatriot scoring his fourth goal of the match nine minutes from the hooter from India's 10th and last short corner.