And then there were eight.
Four men and four women.
Fighting their way through five matches, each has climbed near the summit of the 2006 US Open.
They face a final test before reaching the peak -- the finals.
Belgium's Justine Henin-Hardenne, who has won the international championships of France twice, Australia, and the United States, faces the least-known semifinalist, Jelena Jankovic of Serbia, whose prior greatest claim to fame was her victory in the Australian Open Junior Championships in 2001.
In a second semifinal, France's Amelie Mauresmo, winner of two of the four major international championships this year (Australia and Wimbledon) faces Russia's Maria Sharapova, the 2004 Wimbledon champion who pops out of billboards, Web sites and magazine spreads at the drop of a drop shot.
The winners of these two matches meet Saturday for the US Open women's singles championship.
The Ladies Battle for Supremacy
Who's the women's favorite?
As top seed, Mauresmo has to be rated highly, but Sharapova has shown dogged determination, winning every set of each match, losing only 27 games in that stretch.
Mauresmo survived a second set wipeout against Serena Williams before winning their Round of 16 encounter, 6-4, 0-6, 6-2.
Although Henin-Hardenne is seeded second, she has complained of a painful condition brought on by a bruised rib and side effects of medication that caused her to default in the final of the Australian Open in January.
"I have this problem a little bit from the problems I had in my stomach … in Australia," she said to reporters after her 6-4, 6-4 dismissal of America's Lindsay Davenport in the quarterfinals.
Of her Serbian opponent, Henin-Hardenne offered this opinion: "I'm gonna have a tough semifinal. It looks easy on the paper when you look at the rankings."
Henin-Hardenne is second in the world; Jankovic was seeded 19th here based on her world ranking.
But Henin-Hardenne adds a warning: "Jankovic is playing great tennis this week. It's gonna be a tough, tough one for me."
Russian Roulette in Men's Final Four
The men square off for their semifinals with two Russians popping into the final four, a result that would have drawn laughter a generation ago, when Russian tennis players were synonymous with Russian beauty queens, all perceived to be dumpy and sexless.
Now the Russians are one of the dominant presences in world tennis.
Russian women are among the most feared in tennis, and Russian men wind up intimidating many of the world's top players.
Marat Safin, whose comeback collapsed in Round 16 here at the hands of Germany's Tommy Haas, is a Russian whose victory in the 2005 Australian Open surprised no one.
He won the US Open in 2000. But this year it's Nikolay Davydenko and Mikhail Youzhny who are getting the publicity.
The world's No. 1 men's player for the last three years, Switzerland's Roger Federer, faces Davydenko of Russia, a five-set victor over Haas in the quarterfinals, 4-6, 6-7, 6-3, 6-4, 6-4.
Youzhny of Russia faces Andy Roddick.
Federer conquered a partisan crowd and its favorite son, American James Blake, in four sets, 7-6, 6-0, 6-7, 6-4, in their quarterfinal.
Afterward, Blake called Federer "the best athlete of our time" (better than Tiger Woods or Michael Jordan) for his stamina, skill and versatility in dominating a sport that physically drains its participants every week.
Federer's superlative record, which includes winning the United States, Australian and Wimbledon titles, remains spotless in the US Open competition this year.
Blake took the only set Federer has lost in the five matches he's played.
This year, two Russians surprised the seeding committee and reached the final four.
Davydenko is one. The other, Youzhny, 24, defeated a crowd favorite and second seed, Rafael Nadal of Spain, 6-3, 5-7, 7-6, 6-1, in the quarterfinals.
The unseeded Youzhny will face Roddick, the American on the comeback trail after losing in the first round here last year and suffering a series of painful early losses in Melbourne, Australia; Paris; and at Wimbledon.
Seeded ninth here, Roddick brushed aside Australia's Lleyton Hewitt, 6-4, 7-5, 6-4, in the quarterfinals.
Federer: The Man to Beat
Davydenko, bland but persistent, is a matchstick-thin slugger.
Federer called him "incredibly fit, he never breaks down," but he is not expected to keep Federer away from the final on Sunday.
As the two-time US Open champion, Federer dispatched American Andre Agassi in last year's final and Australia's Hewitt the year before.
This year, on the strength of their play in early rounds, Roddick looks to have the best chance of dethroning Federer.
But best chance is not necessarily a good chance.
What makes Roddick's climb interesting to longtime tennis fans is his budding partnership with Jimmy Connors, who has become an adviser, confidant and coachlike companion.
Roddick credits Connors with rejuvenating his attitude and approach.
So it will be Sharapova's flash and dash up against Mauresmo's solid ground strokes, and Henin-Hardenne's picture-perfect, one-handed backhand against vivacious Jankovic, described by one veteran reporter as "one of the best interviews on the tour."
For the men, make it Federer's fluid strokes against Davydenko's relentless pursuit of the ball and Roddick's newfound fire against Youzhny's newfound power and finesse.
In case anyone's interested, Federer has played both Davydenko and Youzhny before -- seven times each.
Record: Federer 14, Russians 0.
Against Roddick, it's a different story:
The score is Federer 10, Roddick 1.