Top-seeded Alexander Zverev of Germany led Francisco Cerundolo 6-4, 1-0 when the 14th-seeded Argentine retired because of an abdominal injury Saturday night in the National Bank Open. Zverev advanced to face defending champion Alexei Popyrin of Australia in the quarterfinals.

Alexander Zverev made it through to the last eight of the Toronto Masters after Francisco Cerundolo retired due to injury at 6-4, 1-0 on Saturday. The world number three had not won any of his three previous matches against Cerundolo,