Bengaluru, Oct 26 : Delhi's Kushagra Rawat came up with a sensational swim in the 400m freestyle for men as he eclipsed Olympian Sajan Prakashs record on the opening day of the 74th Senior National Aquatic Championships 2021 on Tuesday that also saw two more national records were rewritten at the iconic Basavangudi Aquatic Centre here. Olympian Srihari Nataraj in 100m backstroke and the Karnataka men's quartet in 4x200m freestyle set the other two national records on the first day of action here. Rawat, who narrowly missed making it to the Tokyo Olympics as he could not improve his 'B' qualification time and get the 'A' mark, clocked 3:53.68 to create a new national record, improving on Sajan Prakash's old mark of 3:54.93 seconds set in 2018 at Trivandrum. Rawat was more than three body lengths ahead of second-place finisher Aneesh Gowda of Karnataka, who timed 3:59.66 seconds. Shoan Ganguly of Karnataka took home the bronze with a time of 4:00.14 seconds. In another brilliant swim, Srihari Nataraj improved his own national record of 55.63 seconds in the 100m backstroke for men. Dominating the race right from the start, Nataraj got off to a strong start and was ahead of the pack in the first 50m and extended his lead in the second 50m after a good turn. Though not his personal best, Nataraj clocked 55.10 seconds to set a new national record. Siva S of Karnataka finished second in 57.60 while Zavier Michael D'Souza of Goa won bronze with a time of 58.96 seconds. "It's good to be racing again after the Olympics. Though not my personal best, I am quite happy to have gone under the national record. I have tapered only for seven days for this meet. My focus will be on the FINA World Short Course meet this December in Abu Dhabi," Nataraj, who trains at Dolphin Aquatics under coach Nihar Ameen, was quoted as saying by the organisers. Meanwhile, in the 100m backstroke for women, 14-year-old Ridhima Veerendrakumar shocked Olympian Maana Patel of Gujarat as the youngster from Karnataka beat her to the gold medal. Though Ridhima missed the national record of 1:04.33 held by Maana since 2018, she finished the race in 1:04.40 to take gold. Maana clocked 1:05.31 and Nina Venkatesh of Karnataka finished third with a time of 1:06.39 seconds. An elated Ridhima stated, "I am quite happy to have beaten Maana to a gold medal. She is much experienced than I am and to have won this race feels good. I have raced with her in 2019 where I finished second behind her." In the 50m butterfly for men, two-time Olympian Sajan Prakash lived up to the billing as he clinched the gold with a time of 24.90 seconds. It was a close race with Mihir Ambre of Maharashtra and Adhitya D of TNSA giving him a tough fight but Rajan Prakash, representing Kerala Police, did well to finish the race ahead of both Ambre and Adhitya, who shared the silver medal as both of them clocked 25.08 seconds. In the 4x200m freestyle for men, team Karnataka broke Railways Sports Promotion Board's record set in 2016. The team comprising of Sambhavv R, Aneesh S Gowda, Tanish George Mathew, and Srihari Nataraj clocked 7:37.65 to erase the previous record of 7:45.24. /IANS