Novak Djokovic found his rhythm in the punishing heat to beat Germany's Dominik Koepfer and reach the quarter-finals of the Paris Olympics on Wednesday, staying on track for an elusive gold.
The Serbian top seed, who crushed Rafael Nadal in the previous round, came through 7-5, 6-3 and will face world number 11 Stefanos Tsitsipas in the last eight.