Marketa cruises, Bautista Agut is stunned

Vondrousova won 80 per cent of her first-serve points, 65 per cent of her second, and was an efficient 10/11 at the net.

"I'm happy I won of course, it was a tough match, she's a hometown girl, so it was tough to play against the crowd but I am so happy people are back, I'm enjoying it and I'm so happy about my first win back on Philippe-Chatrier," said the 21-year-old lefty, who fell in the Paris opening round last year to eventual champion Iga Swiatek.

>> DAY 4 RESULTS

Vondrousova will face off with Polona Hercog for a place in the last 16. The 73rd-ranked Slovenian also sunk home hopes on Wednesday with a hard-fought 7-5, 6-4 win over former quarter-finalist Caroline Garcia.

Breakthrough for Henri

Spanish No.11 seed Roberto Bautista Agut was handed a surprising early exit by Swiss qualifier Henri Laaksonen 6-3, 2-6, 6-3, 6-2.

The world No.150 is through to the third round of a Grand Slam for the first time, on his eighth main-draw appearance, and will next play Kei Nishikori, who won a marathon duel on Court Philippe-Chatrier against Karen Khachanov.

Laaksonen fired 53 winners, compared to a meagre 17 from Bautista Agut, and broke the Spaniard's serve six times. This is Bautista Agut's earliest Roland-Garros departure since 2015.

"Today was just amazing match for me. I was playing really aggressive and, yeah, it paid off. I think the conditions were, yeah, I like them here. Yeah, I'm playing forehand well. It's feeling great," said the 29-year-old Laaksonen.

Aces and double faults

German No.6 seed and recent Madrid champion Alexander Zverev kept up his undefeated run against qualifiers at the majors with a 7-6(4), 6-3, 7-6(1) result over Russian world No.182 Roman Safiullin.

Zverev and Safiullin were meeting at tour-level for the first time but they squared off three times during their junior days, including once in boys' singles at Roland-Garros in 2013 (Zverev beat him en route to the final that year).

The former world No.3 fired 15 aces and 10 double faults and next takes on Serbia's Laslo Djere, who defeated his compatriot Miomir Kecmanovic.

Vika and Dasha advance

Two-time major champion Victoria Azarenka, the No.15 seed, passed a tricky test against Danish teenager Clara Tauson 7-5, 6-4 to set up a mouth-watering showdown with 2018 Roland-Garros semi-finalist Madison Keys.

Former quarter-finalist Daria Kasatkina showed no mercy against her good friend Belinda Bencic as she skipped past the Swiss No.10 seed 6-2, 6-2 on Court Simonne-Mathieu.

Kasatkina, who is working her way back up the rankings after dropping from her career-high No.10 (achieved at the end of 2018) to as low as 75 in the world, broke serve four times and faced zero break points during the 76-minute encounter.

The Russian world No.37 fired an impressive 27 winners against just 14 unforced errors and next faces Romanian Sorana Cirstea.

Slovenian 23-year-old Tamara Zidansek followed up the first top-10 win of her career, over Bianca Andreescu in the first round, with a 6-4, 6-1 success over American Madison Brengle in a mere 65 minutes.

The world No.85 had never won a match at Roland-Garros in either of her previous two visits and is now through to the third round of a Grand Slam for the first time in her career.