The 21-year-old from Winnipeg ignited the pro-Canada crowd by beating decorated U.S. Olympian Natalie Coughlin to win the women's 100-metre freestyle.
Canada's swim team rode momentum and crowd support to six medals in six finals, including three gold, on the opening night of swimming.
Audrey Lacroix of Pont-Rouge, Que., won the women's 200-metre butterfly and Van Landeghem capped her night swimming the anchor leg of the 4x100 freestyle relay and besting Coughlin again.
Canada's women beat the U.S. to win the freestyle relay for just the second time in Pan Am history. The first was in Winnipeg in 1999.
Van Landeghem (pronounced VAN LAND-eh-gehm) set both a Canadian and Pan American Games record in the 100 freestyle with a time of 53.83 seconds.
"I think the crowd got me into it honestly," the six-foot-three swimmer said. "I kept saying thank you when I got out of the water because they were amazing. They really pushed me the last 15 metres.
"It's nothing like I've ever experienced just because it was on home soil in Canada. Seeing that flag raised, I was just overcome with so much pride."
With 10 Olympic medals in swimming, Coughlin is tied with Jenny Thompson and Dara Torres for the most by a U.S. woman.
Van Landeghem out-touched the American in freestyle by .23 seconds and also and outduelled her on the last leg of the relay.
"My confidence is sky high right now," Van Landeghem said. "I've don't think it's ever been this high.
"Beating Natalie is obviously huge, but personally, a best time, that's all I could ask for. We're going into worlds in a couple weeks after this to have these performances going into worlds is a huge confidence booster."
Van Landeghem, Toronto's Michelle Williams, Sandrine Mainville of Boucherville, Que., and Montreal's Katerine Savard also posted a national and Pan Am record in the relay with a time of three minutes 36.80 seconds.
"I think this is a once-in-a-lifetime night," Williams said.
Santo Condorelli of Kenora, Ont., took silver in the men's 100 freestyle and Zach Chetrat of Oakville, Ont., earned bronze in the men's 200-metre butterfly.
Condorelli, Calgary's Karl Krug, Calgary's Yiri Kisil and Evan Moerkerke of Tillsonburg, Ont., claimed silver in the men's freestyle relay.
Lacroix cruised to butterfly gold, beating American Katherine Mills by 1.63 seconds. The longest-serving member of the Canadian swim team at 31, Lacroix won Pan Am gold in the same event in 2003.
"I heard the crowd during the second 50 (metres), but by the end of the race I couldn't hear that much," Lacroix said. "I was in my own world praying the wall would come."
"This one is special is because it's at home. It helped my confidence a lot to win last year when I won at Commonwealth Games, but a win tonight in my own pool in Canada was really special and that's what I wanted to experience."
Condorelli and Kisil watched van Landeghem's victory from the ready room as they prepared for the men's 100-metre freestyle.
"We just jumped up and were super-psyched," Condorelli said. "First day and we all medal in each event. I don't think we could ask for a better start."
Competition continues Wednesday at the CIBS Pan Am/Parapan Am Aquatics Centre and Field House.Suggest a correction