The 14th-ranked Williams made quick work of her 19-year-old fellow American in the second set after coming from behind to win a back-and-forth first set.
The seven-time Grand Slam champion will now face either Sorana Cristea or Monica Niculescu in the second round.
It looked like an upset was in the cards in the early going. The 124th-ranked Dolehide, who was making her Rogers Cup debut, jumped to a 3-1 lead in the first set after breaking Williams' serve. One of just two teenagers in the main draw, Dolehide used her heavy service game and aggressive play to challenge Williams on every point.
She finished the match with three aces. Williams had none.
But the 38-year-old veteran broke Dolehide back to take a 4-3 lead, and she did it again in the deciding game of the first set.
Dolehide, one of 12 qualifiers in the main draw, just couldn't maintain the same pace in the second set, as Williams only lost 11 points on her way to victory.
In singles play, 29-year-old Julia Goerges of Germany avoided an early loss with a 3-6, 7-6 (3), 6-4 win over Timea Babos of Hungary in a match that lasted nearly 2 1/2 hours. Goerges had 17 aces and five double faults to Babos' eight and one, respectively.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)