Twelve months ago, Italy's Roberta Vinci ended Serena Williams' hopes of claiming a seventh title at Flushing Meadows.
This time it was the Czech Republic's Karolina Pliskova who halted the 34-year-old American, winning 6-2 7-5 to set up a final today with Angelique Kerber, who beat Caroline Wozniacki 6-4 6-3 in the other semi-final.
For Williams it was a case of déjà vu. For two years in a row she has faced an underdog in the semi-finals of her home Grand Slam event knowing that she was on the verge of creating history.
Last year, Vinci ended Williams' hopes of becoming only the fourth woman in history to complete a pure calendar year Grand Slam and this time she would have broken Steffi Graf's Open era record of 22 Slam singles titles by winning the tournament.
Her defeat also ended her hopes of beating Graf's record of 186 consecutive weeks at the top of the world rankings, which she had equalled this week.
How appropriate it will be that she is replaced by Kerber, another German and a player who grew up with Graf as her idol.
Although Pliskova played superbly and kept her nerve, Williams was suffering from a shoulder injury which she had sustained earlier in the tournament. She also revealed after her defeat that she had also been dealing with "serious left knee problems".
Although Williams declined to go into any details, she explained: "I wasn't able to move the way I wanted to. When you're injured you're thinking of other things when you should be just playing and thinking of your shots. My mind was everywhere.
"Karolina played great. I think if she had played any less then maybe I would have had a chance. I wasn't at 100 per cent, but she deserved to win."
In the fourth round Pliskova beat Williams' sister, Venus, after saving a match point. "You can't do much better than beat both sisters in one tournament," Pliskova said. "It's really special. The match with Venus helped me, not only with the game, but also with the crowd. That was my first match on centre court."
Kerber never looked in danger of losing to Wozniacki. The German has won more main draw matches this year (53) than any other on the women's tour.
"When I was really young I was always dreaming of being World No.1," Kerber said. "It's something really special."