Shaibaz Tumbi and B. Manoj Kumar achieved the feat on Wednesday playing for St Peter's High School against St Philips High School in an under-13 inter-school match at Secunderabad in southern India.
Tumbi hammered 324 off just 116 balls and Kumar 320 off 127 deliveries in an eye-defying display of aggressive batting. The pair smashed 103 fours during their stand but not a single six at the huge Parade ground.
Their feat also eclipsed the previous best stand, in any form of cricket, of 664 between Indian batting superstar Sachin Tendulkar and former Test batsman Vinod Kambli in an inter-school match in Mumbai in February 1988.
"We feel nice to have broken the Tendulkar-Kambli record. We knew our individual scores and were told about the world record only when the innings ended," one of the boys told reporters.
St Philips also conceded 77 extras, including 57 wides and three no-balls, meaning the Tumbi-Kumar duo had 10 extra overs to continue with their run-riot.
"There was a competition between us after reaching 200 that who will complete a triple-century first. We then decided that each will play three balls in an over," said Tumbi.
"I never knew I was breaking a world record. I was just playing for myself and my school. I only realised when I returned to the pavilion that I'd broken a record by scoring a triple-century."
The St Philips batsmen wilted after the onslaught and were dismissed for a paltry 21, losing by a whopping 700-run margin.
Three world records were struck -- highest total, highest stand and highest margin of victory -- in any form of limited-overs cricket at any level, according to former Indian cricket board statistician Mohandas Menon.
The previous One-day record was 630-5 off 45 overs by United Cricket Club against Bay Area in a league match in California, United States, Times of India said.