Russia's Karen Khachanov demolished fourth seed Alexander Zverev of Germany 6-1, 6-2 on Friday to power into the last four of the Paris Masters.
Khachanov, the winner at last month's Kremlin Cup in Moscow, will meet either defending champion Jack Sock or Austrian sixth seed Dominic Thiem for a place in the final.
World number 18 Khachanov saved two match points against John Isner in the last 16 but needed just over an hour to dispatch an out-of-sorts Zverev, who dropped his serve six times in eight games.
Four-time Paris champion Novak Djokovic takes on Marin Cilic in the quarter-finals later on Friday, while Roger Federer will meet Japan's Kei Nishikori.
Djokovic will replace Rafael Nadal as the world's top player on Monday after a two-year absence.
Meanwhile, Federer, 37, is three wins away from his 100th career title after triumphing on home ground in Basel last week.
Khachanov will meet either defending champion Jack Sock or Austrian sixth seed Dominic Thiem for a place in the final.