Serbia's Novak Djokovic and Spain's Carlos Alcaraz stayed on collision course for a golden showdown at the Paris Olympics as they surged through to the quarter-finals on Wednesday.
Djokovic, probably in last-chance-saloon as far as his Olympic title hopes go, beat Germany's Dominic Koepfer 7-5 6-3 to reach the last eight at the Games for a record fourth time.
The 21-year-old Alcaraz, seeded two, then followed suit with a 6-4 6-2 victory over Russian Roman Safiullin.
With Greece's Stefanos Tsitsipas set to play Djokovic in the last eight, the men's singles draw has a familiar feel.
The women's singles quarter-final continued to throw up surprises, however, with Anna Karolina Schmiedlova stunning Wimbledon champion Barbora Krejcikova of the Czech Republic 6-4 6-2 to become the first Slovak since Miloslav Mecir in 1988 to reach the last four in the Olympic singles.
Zheng Qinwen ended the stellar career of Germany's Angelique Kerber in a titanic tussle to emulate Li Na who reached the semi-finals of singles at the Beijing Games in 2008.
Zheng failed to convert three successive match points in the third set as veteran Kerber clung on grimly in stifling heat but eventually prevailed 6-7(4) 6-4 7-6(6) -- collapsing to the red clay in disbelief as Kerber's last shot struck the net.
Three-time Grand Slam champion Kerber announced last week she would retire after the Paris event.
There were mixed fortunes for Americans on day five of the tournament as Tommy Paul ended French hopes of a medal by beating Corentin Moutet 7-6 6-3 to reach the singles quarter-final but Taylor Fritz could not join him, going down 6-4 7-5 to Italy's Lorenzo Musetti.
There was more disappointment for Coco Gauff as the young American and partner Jessica Pegula, the top seeds, lost in the second round of the women's doubles to Czech pair Karolina Muchova and Linda Noskova.