Switzerland's Timea Bacsinszky qualified for her third successive French Open quarter-final with a 5-7, 6-2, 6-1 win over 2002 runner-up Venus Williams and will face Mladenovic next. Despite 16 double-faults, the Frenchwomen was able to pull the upset after the heavy backing of the home crowd.
Nadal secured victory on his third match point when he pushed Bautista Agut to the back of the court with a big forehand that his countryman could only pat back into the net at full stretch.
The 27-year-old, who received an emotional welcome from other players in Paris after her first round at Roland Garros, said she's hoping things will return to normal on the grass.
Bacsinszky delivered a terminal blow for the new guard when she downed 36-year-old Venus Williams 5-7 6-2 6-1.
The fourth seed was nowhere near her best and missed several glorious opportunities throughout the match as her title defence came to a miserable end against the home favourite.
I like Mladenovic to advance to the French Open semifinal.
Tagged one of the pre-tournament favorites after reaching the final in the Madrid and Stuttgart claycourt tournaments, the 13th-seeded Mladenovic is looking to become the first French woman since Mary Pierce in 2000 to lift the Suzanne Lenglen Cup. "It's a very painful defeat here in the French Open".
When Muguruza's complaints about the crowd were relayed to Mladenovic, she said she thought it was just as tough on her, because she had to deal with the burden of thousands counting on her to win.
Muguruza, Venus Win; Bellis Rained-Out in Upset Attempt at French Open
World No. 290 and qualifier Petra Martic reached the last 16 with a 6-1, 6-1 win over Latvian 17th seed Anastasija Sevastova.
"I have proved many times that this is not something that is bothering me at all".
- Eighth seed Kei Nishikori of Japan beat South Korea's Chung Hyeong 7-5 6-4 6-7 (4) 0-6 6-4 after their third-round encounter resumed on Sunday.
Danish 11th seed Caroline Wozniacki knocked off 2009 champion Svetlana Kuznetsova 6-1, 4-6, 6-2 to reach the last eight for just the second time. I think it's just - it's gonna sound weird, but I'm actually happy that this stage kind of the year is done, because I wanted to go as far as possible.
She said in her post-match interview: "It's a match that was eagerly awaited by everyone, myself included". Her best French Open showing was in 2002, when she lost to Serena in the final. Obviously the build up for many on the road to Roland Garros was what it would be like for her coming in as a defending champion.
"I don't know if I have a different culture of sport".
The 47th-ranked Ostapenko is the youngest player in the tournament at age 19.
Ostapenko now faces former No. 1 Caroline Wozniacki, who is a two-time major finalist.