Daniil Medvedev crashed out of the Miami Open on Monday, losing a roller-coaster three-set third-round battle against Argentine Francisco Cerundolo 6-0, 4-6, 7-5.
Medvedev, who reached the final at Indian Wells earlier this month, looked to be heading for a brisk exit after 18th seed Cerundolo raced through the first set in just over 20 minutes.
But Medvedev rallied in the second set to level the match, and there was little to choose between the two in the deciding set.
Cerundolo held to take a 6-5 lead and then scored the decisive break to clinch victory when Medvedev double-faulted on match point.
Medvedev is just the latest highly ranked seed to fall in Miami's early rounds following the exits of world No 1 Carlos Alcaraz, Australian fifth seed Alex De Minaur and eighth seed Ben Shelton.
Canadian seventh seed Felix Auger-Aliassime also bit the dust on Monday, losing in three sets to unseeded Frenchman Terence Atmane.
Atmane, ranked 53rd in the world, powered into the last 16 with a 6-3, 1-6, 6-3 victory in 1hr 53mins.
Another French player also progressed in the men's draw on Monday, with 31st seed Ugo Humbert beating Kazakhstan's Alexander Shevchenko 6-4, 7-6 (7/2).
In the women's draw, Czech 13th seed Karolina Muchova strolled into the quarterfinals with a 6-0, 6-2 rout of Alexandra Eala of the Philippines, advancing to the last eight in just one hour