World number one Simona Halep returned to action in Canada, but she was made to work for her win over Anastasia Pavlyuchenkova.
Boris Becker hailed Rod Laver as "arguably the GOAT of our sport" on the Australian legend's 80th birthday.
German fourth seed Angelique Kerber was surprisingly bundled out of the tournament by Alize Cornet in straight sets on Wednesday.
Benoit Paire showed signs of life late but world number one Rafael Nadal advanced to the last 16 in straight sets at the ATP 1000 event.
Top seed Rafael Nadal saw off Frenchman Benoit Paire 6-2 6-3 in Toronto on Wednesday.
Peng Shuai was sanctioned for attempting to change her doubles partner after sign-deadline at Wimbledon last year.
There were no undue concerns on Wednesday for Novak Djokovic, who beat Peter Polansky in straight sets to reach the Rogers Cup third round.
Juan Martin del Potro withdrew from the Rogers Cup less than three weeks before the US Open, stating that his left wrist needs a rest.
The O2 Arena has staged the prestigious ATP Finals since 2009, but there could be a new venue for 2021.
Home hope Denis Shapovalov and three-time grand slam winner Stan Wawrinka joined Novak Djokovic in the second round of the Rogers Cup.