Monica Seles
Monica Seles (Yugoslavia).
Monica Seles won the French Open Women's Singles title three times in a row in 1990, 1991 and 1992.
Jana Novotna and Helena Sukova
Andres Gomez defeated Andre Agassi 6-3, 2-6, 6-4, 6-4 to win the 1990 French Open Men's Singles championship.
Serena Williams won the 2013 women's singles French Open title.
She was 16.
Monica Seles defeated Steffi Graf in the 1990 French Open.
According to the U.S. Open website (refer to the link, below), the women's U.S. Open singles title was won in 1990 by Gabriela Sabatini.
Andres Gomez
Monica Seles
Darlene Hard
Simone Mathieu