Britain's Andy Murray moved into the last 16 of the Olympic singles, beating Juan Monaco in straight sets.
Murray, the reigning Olympic champion, beat Argentina's Monaco 6-3 6-1 and next faces Italy's Fabio Fognini or Benoit Paire of France.
The Scot, 29, has now won 14 matches in a row since losing the French Open final in June.
Fellow British number one Johanna Konta plays Russian eighth seed Svetlana Kuznetsova later on Tuesday.
Mixed news for Murrays
The draw for the mixed doubles is out and, as things stand, Jamie Murray and Konta will be the only British representatives.