After gaining a crucial break at the end of the first set, Schwartzman took control of the match, defeating the Frenchman 7-5 6-1.
The opening set was an intense contest, with the turning point occurring at 5-5 when Schwartzman displayed his phenomenal defensive abilities to save two break points. The Argentine would go on to hold serve and break in the subsequent game to take the set.
Paire had more difficulty on serve in the second set, in which he made only 42% of first serves and committed seven double faults. No. 8-seeded Schwartzman was able to win the set handily as a result by breaking the Paire serve three times.
Schwartzman has had past success in Canada, reaching the quarter-finals in Montreal in 2017. Up next for the World No. 14 is Spaniard Roberto Bautista Agut, who defeated American Tommy Paul in his second round match.