Tomas Berdych became the first player to reach the last 16 of the Rogers Cup in Toronto on Tuesday night.
The Czech defeated Croatia's Borna Coric 4-6 6-1 6-4 at the Aviva Centre to set up a tie against John Isner or Ryan Harrison.
Elsewhere, John Millman's interest in the competition ended when the Australian retired after just over an hour on court in his first round match against America's Jared Donaldson, who led 6-4 4-3 at the time.
Next up for Donaldson is Fabio Fognini, after the Italian knocked out America's S teve Johnson 6-4 6-4.
The tightest first round match saw France's Lucas Pouille defeat Ecuador's Emilio Gomez 6-7 6-4 7-5, although Croatia's Ivo Karlovic also needed three sets to sink America's Taylor Fritz 6-7 7-6 6-2.
Czech Radek Stepanek had things easier against France's Benoit Paire 6-1 6-3, while America's Rajeev Ram got past Latvia's Ernests Gulbis 6-4 6-2.
America's Dennis Novikov saw off Argentina's Federico Del Bonis 6-4 6-3 and France's Gael Monfils was too strong for Portugal's Joao Sousa, winning 6-3 6-3.
Taipei's Yen-Hsun Lu knocked out Germany's Alexander Zverev 7-5 6-3 and America's Donald Young was another straight sets victor, conquering Ukrainian Alexandr Dolgopolov 7-6 6-4.
Tuesday's final match to finish saw second seed Stan Wawrinka get past Russia's Mikhail Youzhny 7-6 7-6 and set up a meeting against Young or Jack Sock.
Source: PA
