American Venus Williams became the oldest woman to reach the fourth round at Wimbledon since 1994 with a straight-sets victory on Friday at the All England Club in London.
Williams, seeded 10th and a five-time Wimbledon champion, will next face 27th-seeded Ana Konjuh of Croatia, the youngest player remaining in the field at 19 after she ousted No. 8 seed Dominika Cibulkova 7-6 (3), 3-6, 6-4 of Slovakia.
Williams is making her 20th appearance at Wimbledon -- the most among active players -- and had to draw from her years of experience to edge past a determined Osaka. With the victory, Venus ran her Wimbledon winning streak against teenagers to 16-2, with her last defeat to a teen coming in 2004.
Williams and Konjuh will meet on Monday for a spot in the quarterfinals.
Konjuh reached the fourth round at Wimbledon for the first time. She had a 54-22 edge in winners against Cibulkova, who was the runner-up at the 2014 Australian Open.
Azarenka, playing in only her fifth match since giving birth to her first child in December, advanced to the Round of 16 by beating the Brit 3-6, 6-1, 6-4 on Centre Court.
The two-time Grand Slam champion will next meet No. 2 seed Simona Halep, who beat Peng Shuai of China 6-4, 7-6 (7) in another third-round match.
"This is the matches that you're looking for," Azarenka said afterward. "Try to find a way when not everything goes great."
Halep, from Romania, won her only previous meeting against Azarenka in three sets at the 2015 U.S. Open.
"I'm really happy," Halep said after Friday's win. "I think I'm playing better every match. Today was a very high level of tennis. She plays really well. I played well. I'm really thankful with the way that I played and how I've been on court. So everything went pretty good."
Sixth-seeded Johanna Konta kept alive the hopes of ending a 40-year Grand Slam drought by British women after she beat Maria Sakkari of Greece 6-4, 6-1.
Konta become the first British woman to reach the Round of 16 since Laura Robson in 2013.
"I think as a performance, as a competitor, I think I competed really well. It wasn't easy. It was a little bit windy out there, so I think it made it difficult for both of us to play necessarily our best level," Konta said. "I think it was a competitive match. I was really happy with how I put all sorts of difficulties aside and just really looked to compete really hard.
"It was very different than my previous rounds," Konta added. "There was definitely an adjustment period to her ball. She was swinging quite freely. She had great depth on her ball and was definitely challenging me with that. I felt quite clear of what I wanted to try and do out there. I wasn't able to necessarily do it the whole time, but I felt I really knuckled down and tried to stay tough when I needed to."
French Open champion Jelena Ostapenko of Latvia posted her 10th consecutive Grand Slam victory. The 13th-seeded Ostapenko registered a 7-5, 7-5 victory over Italy's Camila Giorgi.
In other third-round matches, fourth-seeded Elina Svitolina of Ukraine eliminated Carina Witthoeft of Germany 6-1, 7-5 and 21st-seeded Caroline Garcia beat American Madison Brengle 6-4, 6-3.