Rafael Nadal sent another ominous warning to his French Open rivals by dropping five games in a third-round win over Italy's Stefano Travaglia.
Travaglia, 28, won just six points in the first set but settled down to make it more of a contest for the Spaniard.
However, Nadal upped the tempo again to set up a meeting with Sebastian Korda.
American 20-year-old Korda became the first qualifier in nine years to reach the fourth round by beating Spain's Pedro Martinez.
Son of the 1992 French Open finalist Petr, Korda won 6-4 6-3 6-1 to reach the last 16.
Korda, who is ranked 213th in the world, had not even won a tour-level match in three previous attempts before impressive victories over Italian veteran Andreas Seppi and American 21st seed John Isner at Roland Garros.
Meanwhile Top seed Simona Halep underlined why she is widely considered the French Open favourite by thrashing American teenager Amanda Anisimova to reach the last 16 at Roland Garros.
Halep won her first Grand Slam title at Roland Garros in 2018 and the next step towards another is a fourth-round match against Polish teenager Iga Swiatek.
Third seed Elina Svitolina also progressed with a straight-set victory.
The 26-year-old Ukrainian won 6-4 7-5 in one hour and 40 minutes against Russia's Ekaterina Alexandrova.