Borna Coric is the last man standing in the way of US Open runner-up Daniil Medvedev earning a rare Russian success in St Petersburg.
Andrey Rublev has claimed some big scalps in 2019, but came unstuck against US Open runner up Daniil Medvedev in St Petersburg on Friday.
Richard Gasquet lost for just the second time in nine career meetings with Benoit Paire in an-all French clash in Metz.
Hubert Hurkacz made Polish history as the third seed stunned Benoit Paire 6-3 3-6 6-3 at the ATP 250 tournament in North Carolina.
Benoit Paire and Hubert Hurkacz will meet in the final of the Winston-Salem Open.
The Winston-Salem Open quarter-finals were pushed back to Friday due to bad weather in North Carolina.
Denis Shapovalov will face Andrey Rublev in the last eight at the Winston-Salem Open.
Denis Shapovalov was untroubled by Tennys Sandgren in the Winston-Salem Open second round.
There were upsets galore at the German Tennis Championships on Monday as Benoit Paire and Cristian Garin were beaten.
Kyle Edmund let a two-set lead slip against Fernando Verdasco, while Stan Wawrinka also lost as Wimbledon champion Novak Djokovic advanced.