She won the final eight games of the match as Wozniacki struggled with her serve throughout.
Wozniacki routinely dispatched resurgent American Sloane Stephens, 6-2, 6-3, to book her spot on the Rogers Cup final in Toronto. She had to play two matches on Saturday after her Friday quarterfinal was postponed due to rain.
All told, Wozniacki won 50 percent of first-serve return points, a number that bested Stephens' mark by 12 percent.
She became the first Ukrainian to reach the Top 10 in the WTA rankings by capturing the Dubai title in February where she beat Wozniacki. "So it was tough for me to close it and I think it's tough to play someone like (that)". Wozniacki leads all WTA players with 46 victories in main-draw matches this season. Even with her semifinal match being quick and painless, it's not easy to bounce back after playing four sets in one day. Pliskova faced a test in the round of sixteen as her opponent, Naomi Osaka, extended the World No. 1 to a third set.
Fifth seed Svitolina, who beat Wimbledon champion Garbine Muguruza 4-6 6-4 6-3 in the quarter-finals, used a strong serve and forehand to control the tempo against Halep.
"The same thing today, I just really went out and played my game". But she had no answers against Wozniacki, whose defensive game undid her attacking all court play.
In doubles, Canadian Gabriela Dabrowski and Latvian Jelena Ostapenko have been eliminated by the Czech Lucie Safarova and Barbora Strycova in two sets of 7-5 and 6-3 in the quarter-finals.
Ukraine's Elina Svitolina has captured the Rogers Cup women's title.
"I didn't win, but I think this whole week was a very big personal victory", Stephens said. "To be in this final once again, it really feels incredible and I feel like I have been playing really good tennis".
Top-seeded Russians Ekaterina Makarova and Elena Vesnina were to meet eighth-seeded Anna-Lena Groenefeld of Germany and Kveta Peschke of the Czech Republic.