World number three Alexander Zverev has reached the quarter-finals of the Vienna Open.

The German only needed 72 minutes to defeat American Marcos Giron 6-2, 7-5 on Wednesday. He will now face either Italy’s Lorenzo Musetti or France’s Gael Monfils.

“He served incredibly well in the second set, so I’m very happy that I managed it in two sets,” Zverev said.

The Tokyo 2020 Olympic champion is still suffering the consequences of a pneumonia, which forced him to skip the China Open in Beijing and the Shanghai Masters.

“I’m not completely fit. It takes months, but I’m feeling better and better,” he said.