Defending champion Andy Murray survived a scare to reach the Olympic men's singles quarter-finals but Johanna Konta exited the women's singles.
Murray fought back after losing eight successive games to register a 6-1 2-6 6-3 victory over Italian Fabio Fognini.
But Konta was beaten 6-1 6-2 in just over an hour by number two seed Angelique Kerber of Germany.
Murray faces Steve Johnson in the last eight, while Konta will play with Jamie Murray in Thursday's mixed doubles.
Andy Murray, the younger of the two Murray brothers, was beaten by Fognini in the Davis Cup in 2014.