In 1988 two young batsmen made the headlines after they put on an unbroken stand of 664, at the time a world record for a partnership in any form of cricket, in a school match in Mumbai. The pair - Sachin Tendulkar, at the time 14 years old, and Vinod Kambli, 16 - both went on to play for India within five years and their record stood for 18 years until it was surpassed by another pair of Indian schoolboys.

Tendulkar and Kambli's record came when their school, Shardashram Vidyamandir, had amassed 748 for 2 in 120 overs spread over two days. But the achievement of Manoj Kumar and Mohammad Shaibaz Tumbi in putting on 721 was all the more remarkable as it came off 40 overs.

The Under-13 match between St Peter's High School and St Phillip's High School in November 2006 was a routine game in the inter-school Brother John of God tournament run by the Hyderabad Cricket Association (HCA). It was the first competitive inter-schools match played by St Phillip's High School and on winning the toss the St Peter's captain Mohammad Akram chose to bat.

While Kumar was a recognised opener, Tumbi usually batted in the middle order but encouraged by news of a double hundred in the same competition a day earlier, he pleaded with the school's coach to be allowed to open. The coach agreed, adding the warning that if he failed he would be dropped. He need not have worried.

Kumar and Tumbi took to the attack from the off, aided by some wayward bowling which contributed 57 wides and three no-balls to the total. What made the achievement even more astonishing was that the score did not include a single six on the large Parade Ground in Secunderabad.

According to a report in The Hindu, the umpires, aware of pleas from the fielders for the pair to stop, decided to end the innings prematurely. "The umpires were also telling us that you just declare and go because they cannot outscore you," Kumar said. "But we said we want to at least complete 300 runs and then more."

Tumbi finished with 324 not out from 116 balls and including 57 fours, while Kumar made 320 not out from 127 deliveries including 46 fours. They offered no respite and only one discernible chance when Tumbi was dropped when he had made 285. "We deserved that slice of luck," he said. "It was our day."

"During our partnership, there was a war of words, with him complaining that I was getting the maximum strike," Kumar said. "So we decided to face three balls each in each over."

The bowling figures predictably did not make happy reading, with two passing a hundred - Majeed finished with 7-0-128-0 and Alexander 8-0-129-0.

As is often the case in such one-sided matches, when it came to their turn to bat St Phillip High School had no appetite and were bowled out for 21 in seven overs. "I was aiming at a 10-wicket haul to emulate Anil Kumble's feat for myself," Akram said after returning figures of 4-1-11-7 with his offspin.

The delighted coach of St Peter's High School encountered a problem when he arrived at the headquarters of the HCA to submit the scorecard from the game. "When they saw 721 from 40 overs, they were stunned and didn't believe me," he said. "It was only when they had confirmed the scores with people from the adjoining grounds that they took the scorecard from me."

As news of the achievement spread, the media starting taking interest and by the next morning the story had made it to national newspaper and television news and a celebration was held at the boys' school.

"We feel nice to have broken Sachin and Kambli's record," Kumar told reporters. "We knew our individual scores and were told about the world record only when the innings ended."

"We were just concentrating on the game," Tumbi added. "We weren't playing to break records but it's a nice feeling that we broke the record of our idol, Sachin Tendulkar. I dedicated the triple hundred to Allah, my coaches, parents, brothers and sisters, and particularly to my driver Vijay Sharma, who sincerely drops me and picks me up from practice every day." But he did admit that "after we had reached some 400 runs at an average of about 20 an over, they had kind of stopped chasing … they were really tired and were just walking and not running behind the balls".

Kambli was contacted for a comment by Cricinfo."It's extremely difficult unless you have some talent," he said. "Our coach used to tell us that thirties and forties are just not good enough. It was tougher for us because school cricket was more competitive at that time. It was largely because of our coach who kept telling us to always try for a big score. Even if we got a double or triple-hundred, he never used to congratulate us. He used to ask, 'Why didn't you stay not out?'"

But VVS Laxman, who had also gone to school in Hyderabad, while congratulating the pair sounded a wise note of caution. "It was a great effort. Apparently they displayed great temperament in not losing their wickets. Definitely these boys of tender age should have a bright future. But I also feel that every effort should be made to see that they are not put under pressure by expectations of a repeat performance. I wish them a great future. My only advice to them is to just put this feat behind and focus on the next games."

Tumbi's father was also wary. "I am now worried and wish that these adulations and felicitations will not hamper them from playing their natural game. Of course, the ultimate dream is to see them don India colours."

If the media were getting carried away, the boys were not. Asked if they were guaranteed their places in the school side, Kumar said he did not think so. "There are players who are better than us. They will also play and try to get the runs. Triple century does not mean that we are on the tree. We have to learn more techniques and think how to get further."

What happened next?

• The boys were awarded cheques of Rs. 5000 each by the head of their school
• Three records were broken - the highest total, highest stand and highest margin of victory in any form of limited-overs cricket at any level.
• The exact whereabouts of the two now is unknown
• A fortnight ago it emerged that the scorebook for the match where Tendulkar and Kambli had achieved their record had been destroyed by the Mumbai School Sports Association. "It's been incinerated as we could not store them all," the association secretary explained. "You cannot expect us to store files that are 25 years old."