Del Potro was rarely troubled as he broke four times to see off the Cypriot’s challenge 6-1 6-2 in 73 minutes and set up a clash with Paul Henri Mathieu who beat Michael Llodra 6-4 6-3.
"I had to find a rhythm," said Mathieu. "He made a lot of first serves today. I had to be focused all the way through the match and I thought I did it pretty good."
France’s Edouard Roger-Vasselin carried on from his shock victory over US Open semi-finalist Stanislas Wawrinka by claiming a 7-5 6-3 win over Tobias Kamke.
Elsewhere, Vasek Pospisil lost just seven points on serve as he defeated Ivo Karlovic 6-3 6-3 and German Daniel Brands beat Lukasz Kubot 6-2 6-4.