Serena Williams beat fourth seed Victoria Azarenka to reach the final of the Rogers Cup in Toronto.
The 29-year-old American won 6-3 6-3 in one hour and 17 minutes against her 22-year-old opponent from Belarus.
She will now face 10th seed Sam Stosur, who ended the winning run of in-form Agnieszka Radwanska.
Poland's Radwanska came into the semi-final on a nine-match winning streak after claiming the Carlsbad title last week but lost 6-2 5-7 6-2 to Stosur.
The Australian got the decisive break at 4-2 in the third and went on to take the match with an ace to reach her second final of 2011. In May she lost to Maria Sharapova in the Rome Masters final.
Stosur, who will return to the top 10 in the world rankings on Monday regardless of what happens in the final, said: "I'm starting to really have things flow again.
"I went through a bit of a dip in form at the start of the season, and I wasn't able to feel like I do now. To come here and play this well, no matter what happens in the final, I'm feeling good."
Williams, who won 93% of her first service points compared to just 54% of her opponent, is now one win away from a second title inside a month ahead of the US Open, which starts two weeks on Monday.
The first set went with serve until Williams broke Azarenka in the sixth game with a cross-court winner.
The players exchanged breaks over the next two games before Williams clinched the set with an ace. She remained in control the rest of the way, breaking Azarenka's serve in the seventh and ninth games to take the match.
The former world number one, who returned to competition in June after 11 months out with injuries and health problems is making only her fourth tournament appearance of the year.
She said: "It was important to take charge from the get-go. I had nothing to lose and had a lot of fun out there.
"It's really cool. I came here trying to do my best. Next thing I know I'm in the final.
"I feel my game is better than it has been in the past couple rounds but I feel it's coming along.
"I still can do better but overall I am almost where I was but I want to exceed that level."