The win enabled India to avenge their 2-3 loss against the same opponents in the last round robin match yesterday.
Ireland's lone goal came from the sticks of Julian Dale in the 48th minute.
India began strongly and earned back-to-back penalty corners in the fifth minute. Though the first attempt was saved, Varun sounded the board from the second chance to hand his side he lead.
India continued their attacking game in the second quarter and achieved success in the 28th minute when striker Shilanand beat Ireland goalkeeper Jamie Carr from close range after being fed by Nilam Sanjeep Xess's fierce pass from right side of the circle.
India's next goal came off Gurjant's sticks in the 37th minute. It was brilliant play by Talwinder Singh, who received a good pass from Simranjeet Singh who laid it to Gurjant and the young striker from Punjab made no mistake in slotting the ball home.
Though India conceded a goal in the 48th minute, the team's defence remained resolute throughout the match restricting Ireland's number of circle entries.
India earned another penalty corner in the 50th minute and another one towards the dying minutes of the match, but they failed to make use of both the opportunities.