For the second year in a row, Serena Williams’ bid to make history ended with a shocking loss in the U.S. Open semifinals.

A seventh title at Flushing Meadows, which would have been an Openera record, will have to wait. So will a 23rd Grand Slam championship, another record. And her 3 1/2-year reign at No. 1 in the WTA rankings is over, too, one week shy of what would have been yet another mark.

Undone by a half-dozen double-faults, including on match point, and plenty of other mistakes she blamed in part on dealing with an injured left knee, Williams was upset 6-2, 7-6 (5) by big-serving Karolina Pliskova of the Czech Republic on Thursday night.

“Karolina played great today. I think if she had played any less, then maybe I would have had a chance,” Williams said. “So I think I wasn’t at 100 percent, but I also think she played well. She deserved to win today.”

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 changed course, saying: “I mean, actually, I do believe it. I always knew I have a chance to beat anyone if I’m playing my game.”

At the 2015 U.S. Open, Williams’ bid for a calendar year Grand Slam ended when she lost in the semifinals to unseeded Roberta Vinci of Italy in one of the biggest surprises in tennis history. This one goes pretty high on the list, too.

This was the 33rd major semifinal of Williams’ career, and the first for Pliskova, who beat the 34- year-old American’s older sister Venus in the fourth round after staving off a match point. Pliskova is only the fourth woman to beat both Williams siblings during the same Slam.

“Obviously, the match with Venus helped me … not only with the game, but also with the crowd,” Pliskova said. “Was my first match on center court.”

And to think: The 24- year-old Pliskova had never been past the third round in 17 previous appearances at majors.

But now she’s on an 11- match winning streak.

“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. Kerber beat Williams in the Australian Open final in January, then lost to her in the Wimbledon final in July.

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