Pospisil, the only seeded player on Monday's schedule, took out 18-year-old Kyle Edmund 6-3, 7-5. Pospisil fought off all four of the break points he faced and won nearly three-quarters of the points on serve.
Edmund also had a solid serving game -- landing 77 percent of his first serves and taking almost two-thirds of the points on serve -- but suffered one break in each set in the loss.
The other three first-round matches Monday were also decided in straight sets. Jiri Vesely topped Jeevan Nedunchezhiyan 7-5, 6-2 with five breaks in 10 games receiving.
Lu Yen-Hsun and Dudi Sela gained second-round spots with wins with identical 6-4, 6-2 scores. Lu defeated Tim Smyczek with six breaks in Smyczek's 10 games serving while Sela eliminated Lukas Lacko by saving five of the six break points he faced.