Angelique Kerber’s first match since capturing the Wimbledon title ended in defeat on Wednesday as the German lost 6-4, 6-1 to Alize Cornet of France at the Montreal WTA event.
World number four Kerber committed 32 unforced errors against the 34th-ranked Cornet in her 85-minute second round loss.
Cornet, 28, goes on to face Ashleigh Barty of Australia in the third round.
It was her second successive victory against Kerber having also triumphed on hard court in Beijing last year.
Del Potro out of Toronto Masters
Third seed Juan Martin del Potro was forced to withdraw prior to his opening match at the Toronto Masters on Wednesday due to a left wrist injury.
The Argentine, who looked to be in good form after reaching the final last week in Los Cabos, was replaced in the draw by Russian veteran Mikhail Youzhny.
Del Potro had a bye into the second round and was scheduled to face Dutchman Robin Haase.
The 29-year-old former US Open champion has struggled with a series of wrist injuries and was almost forced into an early retirement from the sport in 2016.
{{/usCountry}}The 29-year-old former US Open champion has struggled with a series of wrist injuries and was almost forced into an early retirement from the sport in 2016.
{{/usCountry}}