World number one Naomi Osaka's hopes of winning a third successive Grand Slam ended Saturday when she was knocked out of the French Open in the third round by unheralded Katerina Siniakova of the Czech Republic.Japanese top seed Osaka, the reigning US and Australian Open champion, crashed to a 6-4, 6-2 defeat to the 42nd-ranked Czech.“Losing is probably the best thing that could have happened,” said 21-year-old Osaka, the reigning Australian and US Open champion."I felt very tired. In the other matches I had headaches, maybe that's the stress,” said Osaka. "I felt there was a weight on me. This hasn't been the happiest of times."Osaka’s defeat left just four of the women’s top 10 seeds in the tournament including three-time winner Serena Williams and defending champion Simona Halep.Osaka was undone by a shocking 38 unforced errors as she finally ran out of luck in Paris having had to come back from a set down in her first two matches.“I played my best tennis and I hope it continues,” said Siniakova, who was the women’s doubles champion in Paris in 2018 alongside Barbora Krejcikova.Osaka dropped the first set for the third successive match at the tournament, squandering seven break points in all.Siniakova made her pay, breaking for 5-4 and taking the opener when Osaka sent back her 16th unforced error of the set.The Czech, who is the world’s number one doubles player, kept up the pressure on the misfiring top seed, breaking for a 3-2 lead in the second set.Siniakova backed it up with another break for 5-2 off Osaka's third double fault of the match.Victory was hers on Court Suzanne Lenglen when Osaka unleashed another misguided forehand.The Czech goes on to face Madison Keys of the United States for a place in the quarter-finals in what will be her first appearance in the last 16 of the majors.Despite being seeded top for the first time at a Slam, Osaka never looked convincing in Paris. She was two points away from defeat in the first round against Anna Karolina Schmiedlova and came back from a set and break down to see off Victoria Azarenka in round two.Djokovic in Last 16There were no such problems for men's world number one Novak Djokovic who eased into the last 16, stepping up his bid to hold all four Grand Slam titles simultaneously for the second time.The Serbian saw off unseeded Italian Salvatore Caruso 6-3, 6-3, 6-2 to set up a fourth-round tie with either Germany’s Jan-Lennard Struff or Croatian 13th seed Borna Coric."Finally, I think I found my best form in the second set," said Djokovic, who is yet to drop a set in the tournament.It is the 10th successive year the top seed has reached the second week -- and 13th in total -- as he looks for a second French Open title after sealing his first ‘Djoko’ Slam in Paris in 2016.German fifth seed Alexander Zverev needed another five-setter to reach the fourth round, defeating Serbia's Dusan Lajovic 6-4, 6-2, 4-6, 1-6, 6-2.Zverev, whose best run at a Slam came in Paris last year when he made the quarter-finals, will face Italy's Fabio Fognini for a place in the last-eight.Fognini needed four sets to defeat Spanish 18th seed Roberto Bautista Agut 7-6 (7/5), 6-4, 4-6, 6-1.Greek Breakthrough for TsitsipasCrowd favourite Tsitsipas became the first Greek player in 83 years to reach the second week at Roland Garros as he survived a scare against Filip Krajinovic.The sixth seed led by two sets when the match was suspended at 5-5 in the third due to darkness just before 10:00pm on Friday.On the resumption Saturday, Tsitsipas lost the set in a tie-break but sealed a 7-5, 6-3, 6-7 (5/7), 7-6 (8/6) success on Court Philippe Chatrier.The 20-year-old will take on former champion Stan Wawrinka for a place in his second Grand Slam quarter-final.Wawrinka, the 2015 champion and a three-time major winner, recorded his 500th match win with a 7-6 (7/5), 7-6 (7/4), 7-6 (10/8) win over Grigor Dimitrov.As temperatures nudged close to the 30-degree mark, Halep decided not to hang around.The Romanian third seed stormed to a 6-2, 6-1 thrashing of Ukrainian 27th seed Lesia Tsurenko.Halep next faces either Olympic champion Monica Puig or Polish teenager Iga Swiatek.Williams is bidding to reach the second week for the 13th time as she continues her pursuit of equalling Margaret Court's record of 24 Grand Slam titles.The 37-year-old faces fellow American Sofia Kenin who wasn't born when Williams made her debut in Paris in 1998. We'll get through this! Meanwhile, here's all you need to know about the Coronavirus outbreak to keep yourself safe, informed, and updated. The Quint is now available on Telegram & WhatsApp too, Click here to join.