The 19-year-old won the first 10 games of the match and completed his 11th victory in 16 matches (including ATP Challengers) this year with a forehand lob. The World No. 90 won 18 of 25 first-service points in windy conditions in Cagliari and now plays top-seeded Briton Daniel Evans.
Last month, Musetti reached his second ATP Tour semi-final as a qualifier at the Abierto Mexicano Telcel presentado por HSBC, where he recorded his first victory over a Top 10 opponent, Diego Schwartzman. He lost to No. 5-ranked Stefanos Tsitsipas in the Acapulco semi-finals.
Earlier in the day, fifth-seeded German Jan-Lennard Struff saved five match points to overcome Joao Sousa of Portugal 1-6, 6-1, 7-5 in two hours and seven minutes. Struff, who saved three match points at 2-5 down in the deciding set and at 4-5, 15/40, now faces British qualifier Liam Broady.
Marco Cecchinato recorded just his second victory of the season by beating fellow Italian Thomas Fabbiano 6-4, 4-6, 6-3 in two hours and 21 minutes. Cecchinato, who reached his fourth ATP Tour final in October 2020 in Sardinia (l. to Djere), will now challenge Yannick Hanfmann of Germany.