Daniil Medvedev has crashed out of the ATP Tour Masters 1000 event in Indian Wells, with Grigor Dimitrov staging a spectacular fightback to secure victory over the top seed.
Dimitrov trailed a set and a double-break before he turned the match on its head to triumph 4-6 6-4 6-3.
Recently-crowned US Open champion Medvedev had been in dominant form since his breakthrough win at Flushing Meadows and nothing looked set to change as he took the first set and stormed into a 4-1 lead in the second.
But inexplicably the Russian lost his range and Dimitrov reeled off eight games in succession to not only level the match but to establish a strong advantage in the decider.
The Bulgarian duly served out to love to secure his first win over a top-two opponent since 2016 and seal his place in the quarter-finals.
He will face Hubert Hurkacz next after the Polish eighth seed dispatched Russia's Aslan Karatsev 6-1 6-3.
Cameron Norrie reached the last eight of a Masters 1000 event for the first time by defeating Tommy Paul 6-4 4-6 6-2, to move within one more victory of replacing Dan Evans as the British No.1.
The man he must beat to achieve that feat is 11th-seeded Diego Schwartzman, after the Argentine eased past Norway's sixth seed Casper Rudd 6-3 6-3.
Meanwhile, Georgia's Nikoloz Basilashvili accounted for Karen Khachanov 6-4 7-6 (8-6) to advance from the fourth round.