7–6 (7–3), 3–6, 6–4, 1–6, 7–6 (10–7) were the victory figures that finally took the 20-year-old Dane on from the swinging encounter with Argentinian Francisco Cerundolo.
Sixth-seeded Rune was really in trouble at 3-4 and 0-40 in the fifth set. He wriggled out of that grip and later had a chance to serve home the match with a 5-4 lead – but failed.
It was a super tiebreak that had to decide – and then with an impressive stop ball, Rune emerged victorious. Rune suffered a painful loss to Andrev Rublev at the Australian Open earlier this year in the same situation – but now he was the strongest.
"I said to myself when the tiebreak started to just relax, play tennis and enjoy," Rune said after reaching the quarter-finals at Roland Garros for the second year in a row.
In the quarterfinals, fourth-seeded Norwegian Casper Ruud awaits, who got an easier trip in his eighth final. Ruud defeated Chilean Nicolas Jarry 7–6, 7–5, 7–5.
See the stop ball that paved the way for Rune's victory in the player above.