"Really tough to push myself into it and to play the best tennis if you know you're qualified," Pliskova said. "Wasn't being ever in this situation, so I felt weird today."
Venus Williams reaches semifinals at WTA Finals →
"I'm just happy that I don't have to play the next match (against Ostapenko) for qualifying, because last year it was pretty stressful to do that," Pliskova said. "If I win a few matches in a row it gives me confidence."
Venus beats Ostapenko, Pliskova reaches semis at WTA Finals →