Top seed Alexander Zverev has continued his hunt for a first title of 2020 by advancing to the Cologne Indoors semi-finals with a hard-fought 6-4 3-6 6-0 victory over South Africa’s Lloyd Harris.

Having won the first set, Zverev was up 1-0 in the second but dropped two of his four service games as Harris came back strongly to force a third.

The German rebounded as his opponent struggled with a leg injury, and closed out the match.

The seventh-ranked Zverev faces Alejandro Davidovich Fokina in the last four after the Spaniard defeated Dennis Novak 6-3 2-6 6-3.

Another Spanish player, second seed Roberto Bautista Agut, will meet Canada’s Felix Auger-Aliassime in the other semi-final.

Bautista Agut prevailed 7-6 (4) 5-7 6-0 in a tough battle with Hubert Hurkacz of Poland, while Auger-Aliassime had fewer difficulties against Moldova’s Radu Albot, winning 6-3, 6-0.