Two-time Australian Open champion Naomi Osaka staged an impressive comeback to defeat 20th seed Karolina Muchova 1-6, 6-1, 6-3 in the second round on Wednesday. After a thrilling opening-round victory over Caroline Garcia, Osaka overcame a sluggish start to topple last years US Open semifinalist, advancing to the third round of a Grand Slam for the first time since her return from maternity leave.