Rafael Nadal is through however.
Men's second seed Rafael Nadal is safely through to round three of the Australian Open.
The Spaniard beat American Michael Mmoh in straight sets.
Earlier fourth seed Daniil Medvedev won in straights sets against Spain's Roberto Carballes.
American teenager Coco Gauff is out of the tournament.
She was beaten in the second round of the women's singles by Elina Svitolina in straight sets, 6-4, 6-3.
Defending champion Sofia Kenin was knocked out earlier in straight sets by Kaia Kanepi.