Trusov claimed gold in the men's 100m backstroke S7 event and broke the world record with a time of 1:08.14, according to Ukrinform.
Another Ukrainian, Yevhenii Bohodaiko, finished fifth at 1:11.57.
Trusov earlier won silver medals in the men's 400m freestyle and 200m breaststroke events in the Tokyo Paralympics.
Ukraine's national Paralympic team has already won 48 medals - 12 golds, 24 silvers, and 12 bronzes.
It's the first #ParaSwimming medal race of Day 6! Andrii Trusov wins the Men's 100m Backstroke S7 in a World Record time 👏#Gold Andrii Trusov #UKR #Silver Pipo Carlomango #ARG#Bronze Mark Malyar #ISR#ParaSwimming #Tokyo2020 #Paralympics— Paralympic Games (@Paralympics) August 30, 2021