Kerber started her 2018 season with a first ever appearance at the Hopman Cup, where she partnered with Alexander Zverev. She went undefeated in her singles matches and helped the team cruise into the final where they lost to Switzerland. Kerber followed up that performance with her first title in more than a year, at the Sydney International next. To make the final, she edged past Lucie Šafářová and Venus Williams, saving a match point against the former, to make the quarterfinals where she beat Dominika Cibulková. She set up a championship match with home star Ashleigh Barty after moving past Camila Giorgi. There, she beat the Aussie in straight sets for her 11th career title. At the Australian Open, 21st-seeded Kerber moved into the fourth round with wins over Anna-Lena Friedsam, Donna Vekić and former world No. 1 Maria Sharapova, all in straight sets and dropping no more than four games a set. There, she saw off Hsieh Su-wei in three sets to move into her second quarterfinal here, where she swept aside Madison Keys. In the semifinal, a clash against world No. 1, Simona Halep, both had two match points in the third set but neither were converted. The match then ended 9–7 in the third set, with Halep prevailing. Following her strong Australian summer, Kerber returned to the top 10 once again, ranked world No. 9.