Williams said: "I think she played really well".
Illness, but more prominently of late, a knee injury have kept the victor of 23 majors on the sidelines. The 20-year-old American has struggled with Barty in the past, losing both meetings in straight sets. Williams stared her down after sending down one ace.
Williams had one more chance but sent a forehand wide on break point.
It was her way to stay in the game, however, and she claimed the decisive break for 6-5 with a lighting-quick service return that left Williams stranded.
That tournament is among those she might be considering before the grass-court Grand Slam begins on 1 July, along with Nottingham, Birmingham, s-Hertogenbosch, Mallorca and Eastbourne. First time into the R16 at a Slam.
Said her coach, Patrick Mouratoglou: "All I know is, she was not ready".
Osaka admitted that she suffered a lot of stress in Paris.
Still, her level of disappointment at exiting was off the charts.
Osaka is still only 21.
Trump Signs Nice on Map Representing Golan As Part of Israel
Years of exemptions for ultra-Orthodox men have generated widespread resentment among the rest of Jewish Israelis who serve. On the other side, the orthodox parties, which have 16 legislators, wanted the bill to be amended.
Swiatek won't be the only 18-year-old in the final 16.
So, I mean, it's nice to see competitive matches and for I think people to also enjoy matches where nothing's a given, and it can be unpredictable. "I know just what to do".
In fact, the 2019 French Open has been about as chaotic as tennis gets. Always a good match, and we've played them in Grand Slams in the final, semis and now this time in the quarters.
Barty is aiming to become the first Australian to win the Roland Garros title since Margaret Court in 1973.
It felt like her victory over Azarenka could spark a glittering run but it wasn't to be.
She had won her past 16 matches at majors, allowing her to lift the trophies at the US Open last September and Australian Open in January. Greek dark horse Stefanos Tsitsipas completed a darkness-interrupted third-round match to beat Filip Krajinovic, 7-5, 6-3, 6-7 (5-7), 7-6 (8-6), and faces Stan Wawrinka next in a mouth-watering Sunday date after the Swiss 2015 victor saved four set points to complete a 7-6 (7-5), 7-6 (7-4), 7-6 (10-8) win over Grigor Dimitrov. The Romanian showed her best side in a 6-2 6-1 dismissal of Ukrainian 27th seed Lesia Tsurenko.
Zverev faces Monte Carlo Masters victor Fabio Fognini, the ninth seed; Thiem's next opponent is French 14th seed and ex-semi-finalist Gael Monfils.
This latest defeat means Williams' quest of equalling the record of 24 Grand Slam singles titles now held by legendary Margaret Court would wait till the next Grand Slam tournament in Wimbledon. American teen Amanda Anisimova continued her French debut hanging on to beat Irina-Camelia Begu 7-6, 6-4 to advance.
Playing the 16th Grand Slam tournament of his career, Zverev has never been past the quarterfinals. Meanwhile, the 2018 French Open finalist Dominic Thiem of Austria beat hometown favourite Gael Monfils of France 6-4, 6-4, 6-2.
Osaka had not had an easy path since coming to Roland Garros. The fifth-seeded Alexander Zverev was made to work through another five-setter by Dusan Lajovic at 6-4, 6-2, 4-6, 1-6, 6-2.
Keys, a semifinalist in Paris a year ago, advanced by beating qualifier Anna Blinkova 6-3, 6-7 (5), 6-4.