At the 2006 Rogers Cup, she scored the biggest win of her career when she defeated Kim Clijsters (who retired from the match), to reach the third round.

In 2007, Dubois and Renata Voráčová reached the Challenge Bell final but lost to Christina Fusano and Raquel Kops-Jones in straight sets.

Also in 2008, Dubois had three match points against eighth seed Anna Chakvetadze in the first round of Wimbledon but lost with a score of 6–8 in the final set.

She reached at the end of July the second WTA Tour quarterfinal of her career at the Washington Open in College Park, but lost to Tamira Paszek in a match that lasted almost four hours.

At the 2012 Summer Olympics, she teamed with Aleksandra Wozniak to represent Canada in the women's doubles; they lost in the opening round.