The hopefuls of the ATP finals, Andrey Rublev and Denis Shapovalov, will meet in the semi-finals of the St. Petersburg Open after winning straight sets on Friday.
Rublev holds the final automatic qualifying spot for the season-end tournament in London next month after beating Britain's Cameron Norrie 6-2, 6-1.
The third seed was a cut over Norrie, improving his record to 32 wins and just seven losses that year, including three titles.
Shapovalov defeated Stan Wawrinka 6-4, 7-5 in a match between youth and experience. The 21-year-old Canadian won 84 percent of his first service points.
Shapalov's compatriot Milos Raonic defeated his colleague Karen Khachanov 6: 1, 7: 6 (7: 1) and meets Borna Coric in the other semi-final. Coric ousted Reilly Opelka in straight sentences.
Top seed Alexander Zverev moved into the last four of Cologne's interiors on home soil and beat South African qualifier Lloyd Harris 6: 4, 3: 6, 6: 0.
Zverev will face Alejandro Davidovich Fokina in his third semi-final of the year after the unset Spaniard overtook Dennis Novak 6: 3, 2: 6, 6: 3.
Roberto Bautista Agut and the Canadian Felix Auger-Aliassime fight for a place in the final after victories against Hubert Hurkacz and Radu Albot.
Marco Cecchinato and Lorenzo Musetti are hoping for an all-Italian Sardegna Open in their home country after moving up to the last four places on Friday together with the Serbian duo Laslo Djere and Danilo Petrovic.
