Andrey Rublev’s Monte Carlo Masters title defence ended at the first hurdle on Wednesday with a straight-sets defeat by Australian Alexei Popyrin.
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 either compatriot Alex de Minaur or Tallon Griekspoor for a possible quarterfinal 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.