Portugal Colonial - Defending champion Rublev dumped out of Monte Carlo Masters

The Russian never got going in the second-round tie as Popyrin eased to a 6-4, 6-4 win.

The world number 46 will face compatriot Alex de Minaur, who beat Tallon Griekspoor in three sets, for a possible quarter-final against Novak Djokovic.

The loss continued a poor run of form for Rublev, after a defeat in his opening match against Tomas Machac in Miami and losing to Jiri Lehecka in the Indian Wells last 32.

The sixth seed had a break point to level at 5-5 in the second set, but found the net and Popyrin closed out the victory.

Rublev lifted his first Masters 1000 title in Monaco last year by beating Holger Rune in the final.

Australian Open champion Sinner cruised through, though, seeing off American Sebastian Korda 6-1, 6-2.

The world number two converted seven of the 12 break points he created and saved all three of the ones he faced in a dominant performance.

The Italian will next play Jan-Lennard Struff of Germany in the last 16.

Two-time champion Stefanos Tsitsipas showed signs of a return to form, thrashing Argentina's Tomas Martin Etcheverry 6-1, 6-0 in just over an hour.

P.Sousa--PC