Novak Djokovic set up a tantalising clash with Stefanos Tsitsipas in the quarter-finals of the Paris Masters by seeing off Kyle Edmund.
The world number one, who will lose top spot to Rafael Nadal next week, appeared to be under the weather but ground out a 7-6 (9-7) 6-1 victory.
He growled through a post-match interview, his voice indicating all was not entirely well, but Djokovic still had enough in the tank to see off his British opponent.
Edmund ended a losing streak of eight matches when winning through the first two rounds in Paris, and the former top-20 player pushed Djokovic hard in the opening set.
Neither man registered a break, but the contest became one-sided once Djokovic nudged ahead. He clinched his 50th match win of the season in a hurry, claiming 12 of the final 14 points.
Now Tsitsipas awaits the 16-time grand slam champion, with the 21-year-old Greek having won two of his three previous matches against the all-time great.
The most recent of those meetings came in Shanghai just three weeks ago, when Tsitsipas prevailed in a deciding set.
Tsitsipas set up the fourth match in their rivalry by earning a 6-3 6-4 success against Australian Alex de Minaur.
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