France started out as strong candidates, but it started slowly and was shaken by aggressive Mali.
WNBA player Williams scored 14 points, with seven rebounds, six assists and a 12-point assist from Alexia Chartreau to lead France to a 2-1 loss in a tough second set.
France failed to reclaim the level shown on their first stunning day after hosts Australia became upset, but they regrouped after crashing against Canada on Friday.
“It was a tough match. Our recovery was really weak, really,” said France coach Jean-Amy Tauban.
“We need to improve our physical capabilities over the next two games.”
Mali were uncompetitive against Japan and hosts Australia, suffering particularly offensively, but powerful 20-year-old striker Seka Kone (18 points, 18 rebounds) dominated the basket to upset France.
“Our defense was good but we made mistakes (offensive) and France took the opportunity,” said Kony, who was selected by New York Liberty in the WNBA draft earlier this year.
Mali’s physicality spurred the team to a surprising 21-17 lead after the first quarter.
Chartreau’s hot shot put France back in focus, who turned the tide with a better movement of the ball to lead 42-32 at the end of the first half.
France threatened to quit in the third quarter but could not shake the courageous Mali, who gave their best performance in the event to date.
Mali was deeply annoyed when she cut France’s lead to 65-57 midway through the final quarter before Sarah Michelle’s right-handed hat-trick eliminated the challenge.
The top four teams from each of the two groups advance to the quarter-finals.
Later Australia and Serbia will both be looking for a second win in Group B and undefeated Canada could book the quarter-final berth by defeating Asian champions and Olympic silver medalist last year Japan.