Williams lost 6-2, 7-6 (7-5) by big-serving Karolina Pliskova of the Czech Republic on Thursday night.
This was the first major semifinal for Pliskova, who beat the 34-year-old American’s older sister Venus in the fourth round after staving off a match point.
The 10th-seeded Pliskova, who will play No. 2 Angelique Kerber of Germany for the title on Saturday, began her on-court interview by blurting out that she couldn’t believe she’d eliminated Williams to earn a spot in her first major final. Then Pliskova said: “I mean, actually, I do believe it. I always knew I have a chance to beat anyone if I’m playing my game.” “One more step to go,” she said.
Kerber reached her third Grand Slam final of the season — and of her career — by beating two-time U.S. Open runner-up Caroline Wozniacki 6-4, 6-3.