Venus Williams avoided an upset at the hands of fellow American Caroline Dolehide, holding off the 19-year-old 7-5, 6-1 to claim her first round match at the Rogers Cup on Monday.
Williams, coming off a disappointing quarter-final loss at the Silicon Valley Classic last week, fell down a break early but recovered to turn back her dangerous opponent.
"I think she had a really great second serve," Williams told reporters, of Dolehide. "I think I got a better feel for it in the second set. In the first set, I was still figuring it out."
Dolehide displayed her full potential in March when she nearly took down world number one Simona Halep at Indian Wells. Against Williams, the young player lost momentum late as Williams claimed 12 of the final 14 games of the match.
The only two other seeds in action during the opening day were ninth seed Karolina Pliskova and 10th seed Julia Goerges who both won.
Pliskova beat Katerina Siniakova 6-4 6-4 while Goerges overcame Timea Babos 3-6 7-6(3) 6-4.
Among those yet to play are top-ranked Halep and number two Caroline Wozniacki of Denmark. The top eight seeds all received first-round byes.