Wimbledon champion Novak Djokovic saw his bid for a fifth Rogers Cup triumph ended by a shock third-round defeat at the hands of Greek teenager Stefanos Tsitsipas in Toronto on Thursday.
Tsitsipas, who turns 20 on Sunday, beat the 13-time Grand Slam champion 6-3 6-7 (5-7) 6-3 in two hours 18 minutes.
The world number 27 is through to the first ATP World Tour Masters 1000 quarter-final of his career.
World number one Rafael Nadal is also through to the last eight, according to a BBC report.
The Spaniard beat Switzerland's Stan Wawrinka 7-5 7-6 and will play Croatia's world number seven Marin Cilic in the next round.
Second seed Alexander Zverev is next up for Tsitsipas, after the German beat Russia's Daniil Medvedev 6-3 6-2.
Kevin Anderson will play Bulgarian Grigor Dimitrov in the quarter-finals.
South Africa's Anderson, who Djokovic beat in this year's Wimbledon final, saw off Belarus' Ilya Ivashka 7-5 6-3.
Dimitrov beat Frances Tiafoe of the United States 7-6 (7-1) 3-6 7-6 (7-4).
Completing the quarter-final line-up is the match between Russia's Karen Khachanov and Robin Haase of the Netherlands.