Alexander Zverev was given a thorough examination of his Paris Masters credentials by Grigor Dimitrov, but the fourth seed progressed nonetheless to reach the last eight.
Zverev, who was last in last year’s final, saw match points slip from his grasp in the second set as Dimitrov leveled the match. However, he eventually prevailed on Thursday.
World number one Novak Djokovic benefited from a walkover, while Daniil Medvedev also moved through to the quarter-finals of the ATP Masters 1000 event.
Olympic Games gold medalist Zverev had to dig deep for his 7-6 (7-4), 6-7 (3-7), 6-3 win over former world number three Dimitrov.
It was Zverev’s seventh win on the bounce, but he was well aware of just how deep he had to dig to see off a resilient Dimitrov.
“Incredible match,” Zverev, who won a fifth tour title of the year last week at the Vienna Open, said afterwards. “Grigor is playing very high-level tennis and I had to leave everything out there.
“I think it was a very high-level match and it could have gone both ways, especially the third set. I am happy with how things went in the end.”
There was no such ordeal for top seed Djokovic, however.
Djokovic – a 20-time grand slam champion – received a walkover after Gael Monfils was advised not to continue with the tournament due to an adductor issue sustained in his previous win over Adrian Mannarino.
Taylor Fritz awaits five-time Paris champion Djokovic after the American saw off 10th seed Norrie 6-3, 7-6 (7-3), while Casper Ruud will tussle with Zverev.