Peers/Polasek lost just three points on first-serve points and did not face a break point. Their win set a quarter-final clash against Austrians Oliver Marach and Philipp Oswald in Vienna.

Fourth seeds Juan Sebastian Cabal and Robert Farah eked out a narrow victory over Feliciano Lopez and Stefanos Tsitsipas for a semi-final berth. The Colombians hit six aces and converted their sole break point opportunity to defeat the Spanish/Greek duo 7-6(5), 6-7(7), 10-8 in just over two hours.

The team to most recently book its Nitto ATP Finals berth in Turin, Cabal/Farah, missed four match points in the second-set tie-break and another in the match tie-break before its passage was sealed. They await Sander Gille and Dominik Koepfer or top seeds Nikola Mektic and Mate Pavic. Gille/Koepfer scored a 7-6(4), 6-3 win over recent Antwerp champions, Nicolas Mahut and Fabrice Martin.

At the St. Petersburg Open, American duo Taylor Fritz and Tommy Paul combined for a 6-4, 7-5 victory over Uruguayan-Ecuadorian pair Ariel Behar and Gonzalo Escobar. The unseeded partnership will meet Marcus Daniell and Marcelo Demoliner for a place in the semi-finals.

Mexican-Argentine pair Santiago Gonzalez and Andres Molteni also booked a quarter-final spot after they edged past Tomislav Brkic and Nikola Cacic in 91 minutes. Gonzalez/Molteni set a showdown with fourth seeds Hugo Nys and Andrey Golubev following their 4-6, 6-2, 10-7 win.