PARIS — Where would American tennis be without immigrant families?

Just for a start, consider the Samprases, the Agassis and the Changs, whose sons — Pete, Andre and Michael — became Grand Slam champions. But the list is so much longer, the ripple effect so much bigger and the story, which would make a fine book, is adding a new chapter at this French Open.

Of the four American women still in contention in Paris, two of them are young and prodigious talents whose parents came to the United States from present-day Russia. Sofia Kenin and Amanda Anisimova grew up being coached primarily by their self-taught fathers in the professional tennis incubator that is South Florida. Both won their first WTA Tour titles this season, and neither should be unseeded at Grand Slam tournaments much longer.

Kenin, a scrappy 20-year-old ranked 35th, upset Serena Williams in straight sets in the third round on Roland Garros’s center court with much of the crowd against her.

Anisimova, an imposing 17-year-old ranked 51st, is into the round of 16 of a second straight major, and along the way once again eliminated Aryna Sabalenka, the No. 11 seed.