Rafael Nadal was on the receiving end of a stunning upset in the last 16 as second seed Roger Federer survived at the ATP Rogers Cup.
Top seed and 15-time grand slam champion Nadal lost in three sets to 18-year-old Canadian Denis Shapovalov in Montreal on Thursday.
Federer, though, scraped through to the quarter-finals after outlasting David Ferrer.
Meanwhile, German star Alexander Zverev moved into the last eight.
REMEMBER THE NAME
A star was born in Montreal on Thursday.
With Canadian icon Wayne Gretzky watching in the stands, Shapovalov rallied to stun Nadal 3-6 6-4 7-6 (7-4).
After becoming the youngest player to reach the last 16 at an ATP tournament since Nadal in 2004, Shapovalov continued his stellar run despite losing the opening set and falling 0-3 behind in the final-set tie-break.
It ended Nadal's hopes of returning to the top of the ATP rankings as Shapovalov prepares to face Adrian Mannarino, who saw off Chung Hyeon 6-3 6-3 to reach his first 1000 quarter-final.
FEDERER RECOVERS FROM SLOW START
The Swiss maestro did not have it easy against David Ferrer, but unlike Nadal, he managed to see it out.
Federer came back to prevail 4-6 6-4 6-2 over the Spaniard earlier on Thursday.
Losing the opening set snapped Federer's remarkable run of 32 consecutive sets won by the Wimbledon champion.
A last-eight meeting with Roberto Bautista-Agut awaits after he trumped Gael Monfils 4-6 7-6 (7-5) 7-6 (7-2).
IN-FORM ZVEREV SEES OFF AILING KYRGIOS
Zverev finally got the better of his Australian opponent on Thursday.
The talented German claimed a 6-4 6-3 win over Kyrgios, who was hampered by his troublesome hip throughout.
Zverev – who has now reached the quarter-finals or better at four ATP 1000 events this season – will take on Kevin Anderson for a semi-final berth.
Anderson dispatched Sam Querrey 6-4 6-1.
Grigor Dimitrov – the seventh seed – suffered a 7-6 (7-3) 4-6 6-1 defeat to Robin Haase, who saved eight of 10 break points.
Haase will meet Diego Schwartzman after the latter topped Jared Donaldson 0-6 7-5 7-5.