Now it is 10th-seeded Pliskova, who will play Poland's Agnieszka Radwanska or Croatia's Ana Konjuh in the quarters
Karolina Pliskova ruined any chance of another Flushing Meadows sister showdown as she claimed a dramatic 4-6 6-4 7-6(3) win over sixth-seeded Venus Williams on Monday to reach the U.S. Open quarter-finals.
At 36-years-old and the oldest remaining player in the draw, Williams battled until the bitter end as her 24-year-old Czech opponent needed five match points to finally put away the two-time champion.
Since the draw was unveiled tennis fans had circled a potential semi-final between the sport's most famous siblings on American tennis's biggest stage where world number one Serena and Venus have met five times, including twice in the finals.
Now it is 10th-seeded Pliskova, who will play Poland's Agnieszka Radwanska or Croatia's Ana Konjuh in the quarters, that would need to complete a Williams double to reach her first grand slam final.
Serena, looking to continue her drive for a record seventh U.S. Open title, will meet Kazakhstan's Yaroslava Shvedova in a fourth round clash later on Monday.