Swadesh Mondal of Bengal created his fourth national record at the ongoing 37th Sub Junior and 47th Junior National Swimming Championships on Friday.
Mondal came up with a brilliant effort to push a fighting Shoan Ganguly of Karnataka to the second place.
While Swadesh took lead in butterfly, Shoan was ahead in the second hundred where his backstroke was much faster than his competitor from Bengal.
But Swadesh showed his supremacy in the third hundred swimming breast stroke and held on to the lead in freestyle to clinch the race with a time of 4:34.15.
He eclipsed Advait Page's national record of 4:34.76 created in Pune in 2018. Shoan clocked 4:34.39 to take home the silver and Kalp S Bohra of Karnataka clocked 4:43.05 to win the bronze medal.
In another record breaking performance in the 100m butterfly for group II girls, Hashika Ramachandra of Karnataka clocked 1:05.51 to erase statemate Mayuri Lingraj's national record of 1:05.98 created in 2016.
Rishika Mangle of Karnataka won the silver with a time of 1:06.99 and Pratishtha Dangi of Maharashtra won bronze with a time of 1:09.56.
With just one day remaining in the Championship, hosts Karnataka lead the overall medal tally with 134 medals. Maharashtra have 62 medals so far, TNSA have 38 medals and Bengal have 25 medals.