Alexander Zverev eased past Andy Murray’s conqueror Fernando Verdasco to reach the quarter-finals of the Bett1 Hulks Indoors in Cologne.
The top seed, bidding to win his first ATP title since May 2019, won 6-4, 6-1 in just 63 minutes.
“It is nice to be done in just over an hour, especially against Fernando because playing a first match back on hard courts against Fernando can always be tricky,” said Zverev, having seen Verdasco beat Murray in the first round.
“He is one of the most powerful opponents that you can have. I am happy to get the win and happy to be in the quarter-finals.”
Zverev, who was playing his first match since losing in the fourth round of the French Open, will face Lloyd Harris for a semi-final spot.
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Alejandro Davidovich Fokina upset Marin Cilic with a 3-6, 7-6(3), 6-2 win while third seed Felix Auger Aliassime won 6-4, 6-1 against Henri Laaksonen.
Denis Shapovalov reached the quarter-finals of St Petersburg Open after easing to a 6-1, 6-4 win over qualifier Ilya Ivashka. The world No 12 will next face Stan Wawrinka on Friday.
Defending champion Daniil Medvedev is out after losing 2-6, 7-5, 6-4 to Reilly Opelka, who broke in the last game of the second and third sets to beat the top seed.
Borna Coric beat Roman Safiullin in straight sets to reach the last eight while Andrey Rublev won 4-6, 6-4, 7-5 against Ugo Humbert.