Osaka had said then she would boycott news conferences to raise awareness of players' mental well-being, but she did speak to reporters after the defeat by Vondrousova.
All five Australian bowlers claimed wickets with Mitchell Starc taking three for 43 while his new-ball partner Josh Hazlewood took two for 18 from eight overs
The Greek third seed downed American Tiafoe 6-3, 6-4 under the centre court roof at Ariake Tennis Park, where all play on outside courts was delayed an hour by morning drizzle
Dean said a gold medal seemed "a million miles away" when he was consigned to isolation in January after contracting the virus for the second time in five months