Canadian teenager Denis Shapovalov has upset Rafael Nadal in a remarkable three-set victory in the third round of the Rogers Cup in Montreal.
The local boy lost the first set but returned serve to win 3-6 6-4 7-6 (7-4) in two hours and 45 minutes.
Shapovalov advanced to a quarter-final meeting with France's Adrian Mannarino, who defeated Hyeon Chung 6-3 6-3.
Nadal could have overhauled Andy Murray as the world No.1 if he reached the semi-finals of the tournament, but he has been made to wait.
The Montreal crowd was cheering for Shapovalov from the get-go but Nadal got off to a fast start in a high-quality match.
In an impressive display of resilience, Shapovalov held his nerve to win the second and third sets despite coughing up two breaks of serve from 4-1 up in the second set.
Nadal was clearly unhappy with the defeat, which has thrown his US Open preparations off track.
"It's my worst loss of the year because it's a loss to the opponent with the lowest ranking and because I had chance to be No. 1," he told reporters.