Britain's Andy Murray made it through to the last 16 with victory over Juan Monaco of Argentina at the Olympics.
Murray, the reigning champion, won 6-3 6-1 to set up a third-round contest against Italy's Fabio Fognini or Benoit Paire of France.
The Scot, 29, has now won 14 matches in a row since losing in the French Open final in June.
Johanna Konta plays Russian eighth seed Svetlana Kuznetsova in the women's third round later on Tuesday.
Mixed news for Murrays
The draw for the mixed doubles is out and as things stand, Jamie Murray and Johanna Konta will be the only British representatives.