(Refiles amending day in ⁠paragraph one)

PARIS, May 28 (Reuters) - French 17-year-old Moise Kouame ⁠became the fifth-youngest man to reach the third ‌round of a Grand Slam, defeating Paraguayan Adolfo Daniel Vallejo 6-3 7-5 3-6 2-6 7-6(8) in a gripping French Open clash lasting ​nearly five hours on Thursday.

Kouame, ranked 318th ⁠in the world and ⁠playing in his first Grand Slam courtesy of a ⁠wildcard, displayed ‌remarkable composure and resilience to claim the first five-set victory of his fledgling career.

After racing ⁠to a two-set lead, Kouame was pegged ​back as Vallejo ‌launched a fightback, taking the third and fourth sets ⁠to set ​up a decider. The young Frenchman held his nerve and broke back late in the final set.

"Without you I ⁠would never have made it," Kouame told ​the jubilant French crowd, who had been roaring him on throughout. He sealed the win on his first match ⁠point with a daring serve-and-volley in the super tie-break, delighting fans on Court Suzanne Lenglen.

Kouame is the fifth-youngest player to make it to the third round at Roland ​Garros since the Open Era began ⁠in 1968. The youngest remains American Michael Chang, who achieved ​the feat aged 16 in ‌1988.

Kouame will face Chilean Alejandro Tabilo, ​the world number 36, in the next round.

(Reporting by Sybille de La HamaideEditing by Christian Radnedge)