At the end of the 2014 season, Radwańska hired Martina Navratilova as part of her coaching team, with the specific goal of winning a Grand Slam title. She started 2015 by teaming with Jerzy Janowicz to win the Hopman Cup, Poland's first title in the event. The victory included Radwańska's first win over Serena Williams in a singles match. Radwańska competed in Sydney, where she defeated Alizé Cornet but lost to Garbiñe Muguruza in the second round. She reached the fourth round of Australian Open, where she lost to Venus Williams for the first time since 2010, in three sets.