The 26-year-old is the first Greek woman to reach the US Open singles semi-finals. She will take on Britain's Emma Raducanu on Thursday for a spot in her first major final.
"I want to dedicate this win to Greece because we struggled a lot last month with some fire damages," Maria Sakkari said. "So for me winning for Greece, making Greek people proud and happy, especially in difficult times, it makes me even happier because you know how much I love my country."
Maria's win over Pliskova is her third straight win over a Top 10 seed, after defeating No.6 seed Bianca Andreescu in a record-setting Round of 16 wins, and No.10 seed Petra Kvitova in the Round of 16.
Having spent 3 hours and 30 minutes to hold off Bianca in the latest finish of a US Open women's singles match, the big question coming into Wednesday night's quarter-final was how well Maria could physically recover.
She answered the question quickly, with a remarkable serving display that never gave the Czech a chance in the match. Maria broke Pliskova just once in each set but never faced a breakpoint in the match as she served her way to a dominant straight-set win. Her run through New York continues to build on her career-best season, which includes last-four appearances at Roland Garros and Miami Open.
Maria lost just two points on her first serve for the entire match (23 of 25). In total, she lost just eight points on serve.
Despite Maria's domination on serve, Karolina earned one late chance to turn the match around. With Maria serving for the match at 6-4, 5-4, Karolina saved two points from 40-15 to get to deuce for the first time of the night. But with an opportunity to break open a protracted rally with her forehand, she netted a forehand down the line to lose the match.