Madison Keys beat Venus Williams on Monday and was due to play Jasmine Paolini on Wednesday. Victoria Azarenka, on the other hand, withdrew just hours before she was due to take the court in Montreal to play Sloane Stephens.
Montreal was hit with two surprise withdrawals on Tuesday as both Victoria Azarenka and Madison Keys pulled out before their Round of 32 clashes due to injury.
Azarenka was supposed to play the Sloane Stephens but dropped out just hours before as a previous injured flared up.
"Dear fans," she began in a Twitter post. "I am sorry to say, but I have unfortunate news that during my warm up for tonight’s match, I re-injured a lingering injury that I thought was resolved and need to withdraw from the match. Wishing the event all the best success and good luck to Sloane for the rest of the tournament. I love Montreal and I look forward to coming back!"
Meanwhile, Madison Keys, who defeated Venus Williams in Round 1 in Montreal, also pulled out of the tournament due to an injury.
Keys' issue appears to be with the hip, according to tournament organisers.
As a result, her opponent, the Italian Jasmine Paolini, will get a walkover into Round 3.
"I always love playing in Montreal and I’m so sorry to be leaving early," Keys said. "I know the fans will enjoy a great week of tennis, and I look forward to returning in the future."
Both Keys and Azarenka will be keen to resolve their injury issues, with less than three weeks until the final major of the year — the US Open.