Lucy Nicholson/Reuters
MELBOURNE, Australia — It took the two-time Wimbledon champion Petra Kvitova less than an hour on Sunday to beat the American teenager Amanda Anisimova and return to the Australian Open quarterfinals for the first time in seven years.
It took four match points and 2 hours 22 minutes before Ashleigh Barty fended off the 2008 champion, Maria Sharapova, 4-6, 6-1, 6-4 to reach the singles quarterfinals of a Grand Slam event for the first time.
And Danielle Collins took Melbourne Park by surprise, rolling past second-seeded Angelique Kerber, 6-0, 6-2. Collins, 25, entered the tournament ranked 35th in the world, and she had not won a singles match in a Grand Slam tournament.