Second-seeded Matteo Berrettini crashed out of the Firenze Open in the second round on Wednesday, while there were also upsets in the two all-American matches.
Berrettini seemed on the verge of victory when the Italian went up 5-2 in the third set but Roberto Carballes Baena reeled off five games in a row to win 5-7, 7-6 (5), 7-5 and silence the passionate crowd.
“I’m very happy, it’s a very good win for me, the best of my career,” said the Spanish player, who is ranked 80th.
Carballes Baena will face Mikael Ymer in the quarterfinals of the indoor, hardcourt tournament after the Swedish qualifier eliminated fifth-seeded Aslan Karatsev 6-1, 6-7 (6), 6-1.
Fourth-seeded Maxime Cressy and sixth-seeded Jenson Brooksby are also out after losing to fellow Americans.
Cressy was beaten 6-3, 6-4 by J.J. Wolf and Brooksby lost 6-4, 4-6, 6-1 to Mackenzie McDonald in the only remaining first round match.
Wolf will face seventh-seeded Alexander Bublik in the quarterfinals after the Kazakh player beat Corentin Moutet 7-5, 6-4.
Florence is hosting a tour-level event for the first time since 1994