Northern Ireland crashed at home to a 10-man Canadian team to leave Lawrie Sanchez still looking for his first home win as manager.
Striker Olivier Occean peeled away from his marker to head in the only goal on 32 minutes.
Gabriel Gervais had been sent off 10 minutes earlier for yellow card fouls on Keith Gillespie and David Healy.
Substitute Steve Jones almost equalised when he hit the inside of the post with a shot deep into injury-time.
Northern Ireland had other chances but have not won in 11 games at Windsor Park.
Healy will look back on a great chance to draw level in the 38th minute. The Leeds striker somehow managed to head wide in front of the posts following a good cross from Tony Capaldi.
Healy then skipped away from Marco Reda only to smack his shot against the legs of keeper Greg Sutton with the ball then striking the near post.
Sanchez gave Boston's Andy Kirk a chance to impress as a half-time substitute but he had no joy on a disappointing night for Northern Ireland.
Philip Mulryne, Jones and Andy Kirk also came off the bench before Crewe's Jones was denied a late equaliser.
Northern Ireland: Taylor, Baird, Aaron Hughes, Murdock, McCartney, Gillespie, Whitley, Doherty, Davis, Capaldi, Healy. Subs: Carroll, Smith, Kirk, Mulryne, Jones, Williams, Craigan, Clyde.
Canada: Sutton, Gervais, McKenna, Serioux, Imhof, Occean, Bernier, Brennan, Reda, De Rosario, Simpson. Subs: Hutchinson, Hirschfeld, Peters, Klukowski, Hume, Watson.
Referee: Joseph Attard (Malta).