Canada's Denis Shapovalov dropped a 6-7 (5), 6-3, 6-4 decision to Italy's Luca Nardi on Sunday in second-round play at the Cincinnati Open.
Shapovalov, from Richmond Hill, Ont., was seeded 24th at the ATP Tour's Masters 1000 tournament.
Nardi, who entered the main draw as a lucky loser, needed two hours 28 minutes to complete the win.
He'll play 16th-seeded Czech Jakub Mensik in the next round.
Felix Auger-Aliassime and Gabriel Diallo, both from Montreal, won their second-round matches on Saturday.
Auger-Aliassime will play Arthur Rinderknech of France on Monday, while Diallo will take on top-seeded Italian Jannik Sinner.
