Stephens, the world No. 3, has had a productive 2018, winning a hard-court title in Miami in March and making the French Open final, where the 25-year-old by beaten by Halep.
The fluidness and lovely shot making Garcia showed in the Sharapova match was almost invisible when she played the no. 1 Simona Halep. there was a gleamer of brilliant strategies at the beginning of the match when Garcia went up 3-2 and the commentator even remarked that "You can begin to feel that the Garcia momentum is building".
With the win Stephens advances to her second consecutive Rogers Cup semifinal after falling to Caroline Wozniacki a year ago.
She then raced through the second set 6-1 with minimum fuss.
The timing of the match, in the afternoon, had upset Halep after her Friday evening quarter-final win.
American Sloane Stephens faced little resistance in her 6-2 6-2 win over Latvia's Anastasija Sevastova in a match that took a little over an hour to complete.
"I think the match was a very good level of tennis even if the rhythm was a little bit mixed".
"I think I talked enough about it", she said. "Just going to kind of take it all in, realize I did a good job this week, and I can be proud of myself for that".
Halep fended off four set points to claim a back-and-forth first set in a tiebreak after storming to a 4-1 lead before U.S. Open champion Stephens fought back to level.
Stephens added three more breaks to take the second set, but lost her serve to open the third.
Stephens led throughout the second set, breaking Halep twice, but the Romanian took control of the third set, turning a break into a 5-2 advantage.
Australian No.1 Ashleigh Barty is just one match away from a maiden Canadian Open finals appearance after defeating Belgian Kiki Bertens in straight sets.
"I love to play in Canada", she said.