Canada's Gabriel Diallo, Marina Stakusic fall in qualifying at National Bank Open
Auger-Aliassime lone seeded Canadian at 6, Leylah Fernandez 13th on women's side
Canada's Gabriel Diallo dropped a 6-2, 2-1 decision to Hugo Gaston of France in qualifying play on Sunday at the National Bank Open in Montreal.
The match ended after 58 minutes when the 20-year-old Montrealer was forced to retire due to heat exhaustion.
Diallo, a wild-card entry who plays for the University of Kentucky, was the lone Canadian to reach the second round of the 28-man qualifying draw.
Play was suspended due to rain later Sunday with two matches yet to be completed.
Meanwhile, fellow Canadian Marina Stakusic also came up short in her bid to play in the women's tournament in Toronto.
With the win, Gaston earned one of seven qualifier berths in the men's 56-player main draw starting Monday at IGA Stadium.
Fabio Fognini of Italy also advanced with a 6-3, 4-6, 6-2 victory over Germany's Daniel Altmaier and Benoit Paire of France beat Marc-Andrea Huesler of Switzerland 6-3, 3-6, 6-1.
4 Canadian men in main draw
Arthur Rinderknech of France defeated Japan's Taro Daniel 6-4, 6-4 and Britain's Jack Draper beat Quentin Halys 3-1 after the Frenchman retired.
Montreal's Felix Auger-Aliassime is the only seeded Canadian player at No. 6. Denis Shapovalov of Richmond Hill, Ont., is also in the main draw along with wild-card entries Vasek Pospisil of Vernon, B.C., and Alexis Galarneau of Laval, Que.
Defending champion Daniil Medvedev of Russia is the top seed at the $6.57-million US ATP Tour event, which runs through Aug. 14.
In Toronto, the 17-year-old Stakusic from Mississauga, Ont., lost to Tereza Martincova of the Czech Republic 6-4, 4-6, 6-1 in the second round of the WTA event's qualifying tournament.
Stakusic had hoped to become the sixth Canadian playing in the tournament's main draw starting on Monday.
There are eight qualifying spots up for grabs at Toronto's Sobeys Stadium complex on Sunday.
Leylah Fernandez of Laval, Que., is the highest ranked Canadian in the draw, seeded 13th.
Former champion Bianca Andreescu of Mississauga, Vancouver's Rebecca Marino, Carol Zhao of Richmond Hill, Ont., and Toronto's Katherine Sebov are already in the main draw of the women's tournament.