The two-time Olympic medallist clocked a time of three minutes and 47.50 seconds for the fifth-fastest time in the world this year. He beat out fellow Victoria native Jeremy Bagshaw, who finished second in 3:49.76.
''We're going through one of the hardest years of training,'' said Cochrane, who will race his signature 1,500 freestyle on Saturday. ''There's been a lot of ups and downs but still it's been an awesome week of swimming. It's super inspiring to see how well the younger swimmers are performing."
Noemie Thomas of Richmond, B.C., won the women's 100 butterfly while also being added to the worlds and Pan Am Games team. She edged Katerine Savard of Pont-Rouge, Que., 58.17 to 58.18.
Dominique Bouchard of North Bay, Ont., and Hilary Caldwell of White Rock, B.C., finished one-two in the women's 200 backstroke. Bouchard swam the race in 2:09.05 while Caldwell was nearly three seconds off her Canadian record time in 2:09.53.
Calgary's Russell Wood captured the men's 200 backstroke in 1:59.18. He broke the national mark in the 50-metre race on Thursday and neared the Canadian record in the 100 on Wednesday. All three wins were personal bests.
Emily Overholt of West Vancouver, B.C., won the 400 freestyle with a personal best 4:10.07. Taylor Ruck finished in fourth but broke Shannon Smith's national age group record for 13-14 year olds which had stood since the 1976 Olympics in Montreal.
Richard Funk of Edmonton and Rachel Nicol of Lethbridge, Alta., won the 50 breaststroke.
The competition is a test event and qualifier for the Pan Am Games in Toronto from July 10-26. Competitors are looking to secure spots on the Canadian teams for the world championships in Kazan, Russia from July 24-Aug. 9.