The 17-year-old Andrew, whose age-group success has seen him tipped as a multi-medal threat in the mold of Olympic superstar Michael Phelps, on Friday won the 100m individual medley in 51.84sec.
He edged Japan's Rio Olympic bronze medallist Daiya Seto, who took silver in 52.01 with Japan's Shinri Shioura earning bronze in 52.17.
World record holder Vladimir Morozov settled for equal sixth, shortly after anchoring Russia to victory in the men's 4x50m freestyle relay.
Aleksei Brianskii, Nikita Lobintsev, Aleksandr Popkov and Morozov clocked 1:24.51 to claim gold ahead of the United States and Japan in the sprint relay that opened the evening's action.
Their triumph came on the same day as another damning report on state-backed doping in Russia.
Canadian investigator Richard McLaren released a new report in London saying that more than 1,000 Russian athletes were involved in or benefitted from efforts to conceal positive tests.
Amid renewed calls for banning Russia from international sports, the country's swimmers stuck to business in Windsor, bookending the night with a victory in the men's 200m freestyle relay.
Mikhail Dovgalyuk, Mikhail Vekovishchev and Artem Lobuzov had Russia lying fourth when anchor Aleksandr Krasnykh hit the water. He powered to the front for a victory in 6:52.10, with the United States second in 6:53.34 and Japan third in 6:53.54.
Puts pulled off the upset in the men's 50m freestyle, pulling away in lane seven to win in 21.10sec and edge Russia's Morozov by four one-hundredths of a second.
Lithuania's Simonas Bilis settled for bronze in 21.23.
Hungarian Katinka Hosszu's gold medal binge continued with a triumph in the 100m individual medley -- her fifth gold of the championships.
Hosszu clocked 57.24 to take the gold ahead of Australian Emily Seebohm (57.97) with bronze going to Jamaican Alia Atkinson (58.04).
Swimming's "Iron Lady," winner of three gold medals at the Rio Olympics, added another crown to those she had already earned this week in the 200m butterfly, 100m and 200m backstroke and 400m individual medley.
American Leah Smith added 400m freestyle gold to the 800m free title she won on Thursday, powering away from tenacious Russian Veronika Popova to win in 3:57.78.
Popova clocked 3:58.90 for silver and Japan's Chihiro Igarashi earned bronze in 3:59.41.
Japan's Junya Koga won the men's 50m backstroke in 22.85sec, holding off France's Jeremy Stravius (22.99) with Pavel Sankovich (22.03) taking bronze.
Denmark's Jeanette Ottesen won the women's 50m butterfly, surging on the final half-lap to win in 24.02 ahead of American Kelsi Worrell and Japan's Rikako Ikee.