Egor Gerasimov followed up his win over Andy Murray in Montpellier by powering past a man who once played second fiddle to the Scot.
The Belarusian saw off Aljaz Bedene, with a 6-4 7-6 (7-4) win carrying him through to the quarter-finals of the Open Sud de France.
Bedene was British number two to Murray heading into Wimbledon in 2016, when the Scot won his third grand slam title, but has since reverted to representing his native Slovenia.
He put up a fight against Gerasimov, who sank Murray in straight sets on Tuesday, but the 28-year-old from Minsk took three of his five break-point opportunities and held his nerve in the tie-break to advance.
The success for Gerasimov sets up a last-eight clash with Spain's Alejandro Davidovich Fokina, who scored a fine 7-5 6-2 win over Polish fourth seed Hubert Hurkacz.
Top seed and world number 13 Roberto Bautista Agut raced to a 6-0 6-3 victory over French qualifier Gregoire Barrere, but Croatian third seed Dusan Lajovic tumbled out, losing to Dennis Novak in straight sets.
At the Singapore Open, second seed John Millman fell by the wayside, the Australian slumping 6-4 6-1 to compatriot Matthew Ebden.
French top seed Adrian Mannarino encountered no such problems, ending the hopes of Roberto Marcora with a 6-3 7-5 win to join Ebden in the quarter-finals.