India crushed arch-rivals Pakistan by 203 runs in their Under-19 World Cup semi-final in Christchurch Tuesday to set up a tournament decider against Australia.

An unbeaten century from Shubman Gill helped India set a competitive total of 272, which Pakistan never looked like reaching as they were skittled for 69 with more than 20 overs remaining.

Ishan Porel was India's hero with the ball, taking four for 17 in a match the tournament favourites utterly dominated.

“It was a good performance from everyone... we did a really good job,” captain Prithvi Shaw said.

It was the Pakistan youth team's third-lowest total on record, underlining the batting woes of a team that failed to score more than 200 during the tournament in New Zealand.

Poor fielding also undermined Pakistan's chances as they squandered seven run-out chances.

“Unfortunately our batsmen didn't really perform and nothing really worked out from the start,” Pakistan skipper Hassan Khan said. “We missed a couple of chances and things didn't really go our way.”

The result sees India square off against fellow heavyweight Australia in Saturday's final in Tauranga.

Both sides have won the tournament three times, with India winning its last title in 2012 when they defeated Australia in the final.

India are unbeaten in New Zealand, with five convincing wins from five matches, including a 100-run win over Australia in the group stages.

Australia also looked vulnerable in their quarter-final against England before a record-breaking eight-wicket spell from leg-spinner Lloyd Pope turned the match.

Against Pakistan, the Indians won the toss and elected to bat first, with openers Shaw and Manjot Kalra scoring at better than a run a ball in the early overs.

Pakistan's vaunted pace attack, which fired them into the final four, failed to make inroads as fielding errors saw Kalra dropped twice.

The 89-run opening partnership was finally broken when Shaw was run out for 41, with the TV umpire ruling he failed to ground his bat properly while diving for safety.

Kalra departed on 47 but India still appeared set for a big total until paceman Arshad Iqbal slowed their momentum with three wickets in as many overs.

Muhammad Musa helped mop up the tail, ending with figures of four for 67 but Gill continued his rich vein of form at the tournament to ensure India's total was competitive.

He steadied the middle order and brought up his 93-ball century in the final over, finishing on 102 not out.

Pakistan made a disastrous start, slumping to 28 for four as Porel tore through their top order. Shaw led the way in the field with two sharply-taken catches.

Only three Pakistan batsman reached double figures, with Rohail Nazir top-scoring on 18 in a one-sided contest.