Raj Kumar Pal scored an early goal that proved to be the winner for India.
Malaysia's 5-0 win over Japan early in the day meant that an outright win became a pre-requisite for India to qualify for the summit clash.
South Korea defeated Japan 3-1 in another Super 4 match to move to four points.
The defending champions avenged their 2-5 defeat to Japan in the pool stage.
The massive win for Indian men's team shut the door for Pakistan.
Asian champions Japan thrashed India 5-2 in a Group-A league match in men's Asia Cup in Jakarta.
India and Pakistan have won the tournament three times each, while South Korea are the most successful team, having clinched the title four times in the 10 previous editions.
Hockey India on Monday named a 20-member squad for the tournament, which is a World Cup qualifier.
The tournament, that usually alternates between ODI and T20I formats, was last played in 2018 and won by India.
Sharmila Devi and Gurjit Kaur scored for India in the playoff.