Casper Ruud's hopes of building on his victory at the Barcelona Open were ended as he lost to Felix Auger-Aliassime at the Madrid Open. (More Tennis News)
Auger-Aliassime will now face top seed Jannik Sinner in the quarter-finals, after claiming a 6-4 7-5 victory over the fifth seed Ruud on Tuesday.
Ruud, runner-up at last year's French Open and a force to be reckoned with on clay, won in Barcelona earlier in April, but came unstuck against the Canadian.
It was not the only shock exit, as Alexander Zverev, the world number five, succumbed in straight sets to Francisco Cerundolo.
Earlier, Daniil Medvedev claimed his place in the quarters, in which he could face Rafael Nadal, by beating Alexander Bublik 7-6 (7-3) 6-4.
Data Debrief: Medvedev's milestone
Five of the six quarter-finals Medvedev has reached on clay have come at either ATP Masters 1000 or grand slam level.
He has now reached at least the quarter-final stage at all nine Masters events, too.
