Paris - Chinese second seed Li Na crashed out of the French Open first round on Tuesday in a 7-5, 3-6, 6-1 defeat against world number 103 Kristina Mladenovic of France.
Following men's third seed Stan Wawrinka's exit on Monday, fellow Australian Open champion Li became the biggest early victim in the women's draw as 21-year-old Mladenovic stormed through the third set.
It was another disappointing exit for Li, who won in Paris in 2011 but hasn't been past the fourth round in six other appearances.
On Tuesday, she committed 37 unforced errors.
Mladenovic now meets Alison Riske of the United States in the second round.
"It's just incredible, I don't have the words to describe what happened," a tearful Mladenovic said.
"To beat the world number two in the first round at Roland Garros is incredible. Without you, I couldn't have done it," the 2009 French Open junior champion told the crowd.
The 21-year-old dug deep to steal the first set from under Li's nose when she saved two set points at 5-4 before levelling the match.
It was a mighty effort from the 1.84m (6ft) right hander and she seized on a lapse by Li to close out the set 7-5 in just over an hour.
Li, who came into the tournament in good form, having reached the quarter-finals at Rome and Madrid as well as the Miami Masters final where she lost to Serena Williams, immediately hit back to start the second set.
The 32-year-old from Wuhan picked up an early break to race into a 3-0 lead which she protected the rest of the way to level the match 6-3.
Mladenovic, who teamed up with Canadian Daniel Nestor to win the Wimbledon (2013) and Australian (2014) mixed doubles titles, was the first to draw blood in the final set when she broke in the fourth game to jump into a 4-1 lead.
The match was slipping away from the Australian Open champion while Mladenovic grew in confidence knowing victory was within her grasp.
However the Chinese world number two was unable to muster a fightback as Mladenovic, who has only reached the second round twice now in six appearances at Roland Garros, closed out the match 6-1 for her most memorable singles' victory.Results on Tuesday at the French Open, the third day of the season's second Grand Slam tournament at Roland Garros (x denotes seeded player):
Jack Sock (USA) bt Nicolas Almagro (ESP x21) 5-0 - retired (foot)
Dusan Lajovic (SRB) bt Federico Del Bonis (ARG) 6-3, 6-2, 6-3
Jurgen Zopp (EST) bt Tommy Haas (GER x16) 2-5 - retired (shoulder)
Ivo Karlovic (CRO) bt Grigor Dimitrov (BUL x11) 6-4, 7-5, 7-6 (7/4)
Andreas Haider-Maurer (AUT) bt Daniel Brands (GER) 4-6, 4-6, 6-2, 6-3, 6-4
Axel Michon (FRA) bt Bradley Klahn (USA) 6-1, 6-7 (4/7), 5-7, 6-1, 6-4
Kevin Anderson (RSA x19) bt Stphane Robert (FRA) 7-5, 6-3, 6-4
Andreas Seppi (ITA x32) bt Santiago Giraldo (COL) 6-3, 7-5, 6-3
Juan Monaco (ARG) bt Lucas Pouille (FRA) 6-3, 6-1, 6-4
Simone Bolelli (ITA) bt Andrea Arnaboldi (ITA) 6-4, 6-4, 6-2
David Ferrer (ESP x5) bt Igor Sijsling (NED) 6-4, 6-3, 6-1
Richard Gasquet (FRA x12) bt Bernard Tomic (AUS) 6-2, 6-1, 7-5
Carlos Berlocq (ARG) bt Lleyton Hewitt (AUS) 3-6, 6-2, 6-1, 6-4
Pablo Cuevas (URU) bt Matthew Ebden (AUS) 6-1, 6-2, 6-3
Philipp Kohlschreiber (GER x28) bt Pere Riba (ESP) 7-5, 6-4, 6-1
Denis Istomin (UZB) bt Sergiy Stakhovsky (UKR) 6-3, 6-4, 2-6, 6-3
Camila Giorgi (ITA) bt Bojana Jovanovski (SRB) 6-4, 6-3
Svetlana Kuznetsova (RUS x27) bt Sofia Shapatava (GEO) 6-3, 6-1
Elina Svitolina (UKR) bt Petra Martic (CRO) 5-0 - retired (wrist)
Ana Ivanovic (SRB x11) bt Caroline Garcia (FRA) 6-1, 6-3
Sloane Stephens (USA x15) bt Peng Shuai (CHN) 6-4, 7-6 (10/8)
Polona Hercog (SLO) bt Jana Cepelov (SVK) 6-2, 6-3
Mara Teresa Torr (ESP) bt Klara Zakopalova (CZE) 7-6 (7/4), 6-2
Magdalna Rybrikov (SVK) bt Urszula Radwanska (POL) 4-6, 6-4, 3-0 - retired
Heather Watson (GBR) bt Barbora Zhlavov Strcov (CZE) 6-3, 6-4
Simona Halep (ROM x4) bt Alisa Kleybanova (RUS) 6-0, 6-2
Jelena Jankovic (SRB x6) bt Sharon Fichman (CAN) 5-7, 6-1, 6-3
Teliana Pereira (BRA) bt Luksika Kumkhum (THA) 4-6, 6-1, 6-1
Sorana Cirstea (ROM x26) bt Aleksandra Wozniak (CAN) 6-7 (3/7), 7-5, 6-2
Kirsten Flipkens (BEL x21) bt Danka Kovinic (MNE) 7-6 (8/6), 6-2
Julia Glushko (ISR) bt Donna Vekic (CRO) 7-5, 2-6, 6-4
Dinah Pfizenmaier (GER) bt Estrella Cabeza (ESP) 4-6, 6-3, 6-3
Yanina Wickmayer (BEL) bt Caroline Wozniacki (DEN x13) 7-6 (7/5), 4-6, 6-2
Silvia Soler (ESP) bt Chanelle Scheepers (RSA) 6-2, 6-3
Kiki Bertens (NED) bt Alexandra Cadantu (ROM) 7-6 (7/5), 6-1
Anastasia Pavlyuchenkova (RUS x24) bt Kimiko Date Krumm (JPN) 6-3, 0-6, 6-2
Alison Riske (USA) bt Mirjana Lucic (CRO) 7-6 (7/2), 6-3
Kristina Mladenovic (FRA) bt Li Na (CHN x2) 7-5, 3-6, 6-1