Kerber kicked off the 2019 season with her second appearance at the Hopman Cup, alongside Alexander Zverev once again; they lost in the final to Switzerland in a rematch of last year's final. In Sydney, Kerber failed in her title defence bid with a loss to eventual champion Petra Kvitová in the quarterfinals. At the Australian Open, second-seeded Kerber moved into the last 16 with straight-set wins over the likes of Polona Hercog, Beatriz Haddad Maia (gaining her 100th Grand Slam match win) and Kimberly Birrell, only to be upset by eventual semifinalist Danielle Collins in straight sets. The following month, Kerber made the semifinals at the Qatar Open where she lost to eventual champion Elise Mertens. At the Dubai Tennis Championships, Kerber lost in the third round to eventual semifinalist Hsieh Su-wei in three sets.