The tall power baseliner, who ripped winner after winner on the clay of Paris, also surprised the French crowd with a skin colored underpants.
Williams, who has posted a WTA Tour best record this year of 27-4, was met with whistles and catcalls and after the match was not sure if she would again wear the eye-catching outfit again during the competition.
By reaching the WTA Tour world number two ranking, Williams assured herself that she could not meet Serena Williams until the final.
However Williams could face an early French Open test from the extreme power hitter and French favorite Arvane Rezai in the fourth round. The fifteenth seeded Rezai of France upset Williams earlier this month in the Madrid WTA Tour final 6-2, 7-5 after the American had held several second set setpoints.
Williams, who has won seven total singles grand slam titles, has never won the singles title at the French Open, known in France as Roland Garros. In 2002, Williams scored her best Paris singles result in a final round loss to her sister.
But due to an arguably fragile and injury prone body, Williams has oftentimes turned in uneven results on the physically demanding clay surface at Paris including an unexpected 6-0, 6-4 loss to the little known Agnes Szavay of Hungary last year in the third round.