PARIS (Reuters) - Slovakian teenager Anna Schmiedlova deprived Venus Williams of a likely third-round meeting with her sister Serena at the French Open when she beat the American 2-6 6-3 6-4 in the second round on Wednesday.
Under grey skies on court Philippe Chatrier, 29th seed Williams got off to a solid start, winning four games in a row to take the opening set.
World number 56 Schmiedlova, however, stepped up a gear and, after an early exchange of breaks, stole the nine-times grand slam champion's serve in the seventh game of the second set and levelled the contest when her opponent netted a forehand.
Schmiedlova, 19, pulled through thanks to a series of jaw-dropping passing shots to set up a possible meeting with defending champion Serena Williams who was playing Spain's Garbine Muguruza later on Wednesday.
"It's the biggest win of my life," an emotional Schmiedllova told a courtside interviewer.
"It was incredible. Now I want to beat the other one."
Since losing in the fourth round of Wimbledon in 2011, Venus Williams has lost in the first or second round of every grand slam she has taken part in, except for the 2013 Australian Open, where she reached the third round.
Williams was diagnosed with an auto-immune disease in September 2011 and she has won only two WTA titles, in Luxembourg in October 2012 and Dubai in February this year.
Schmiedlova, on the other hand, is on the way up, having started to climb the rankings ladder since losing the Roland Garros juniors' final in 2012.
(Reporting by Julien Pretot; Editing by Robert Woodward)