India's victory at the Sultan Qaboos Sports Complex in Muscat meant that Asian champions Japan - who had earlier edged one point ahead of South Korea after earning a 1-1 draw against Pakistan - were confirmed as the fourth semi-final qualifiers.

After falling two goals behind in 10 minutes - courtesy of Harmanpreet Singh and Gurjant Singh - the Koreans rallied and narrowed the lead to 2-1 by half time thanks to a goal by captain Lee Seungil.

It was not until the final quarter that India pulled away as Harmanpreet Singh completed his hat-trick with goals in the 47th an 59th minute.

Kenji Kitazato had given Japan a 12th minute lead against Pakistan, and although it was equalised after 25 minutes by Mubashar Ali, the Japanese held on to earn the point that eventually earned them progress to the last four.

India, who got their trophy defence underway with an ominous 11-0 win over the hosts, have thus won four of their five round robin matches - their other match being a 0-0 draw with Malaysia, currently second in the group, three points ahead of Pakistan with an identical goal difference of plus seven.

India are now virtually certain to finish top of the group of six nations, but must await tomorrow's final two round robin games, in which Malaysia play Pakistan, before knowing who their semi-final opponents will be.

Japan, meanwhile, will finish with a match against Oman, who have yet to earn any points.