Bertens started off her clay-court season at the Charleston Open as defending champion. Bertens reached the third round before losing against Maria Sakkari in straight sets. After that, Bertens reached the semifinals at the Porsche Tennis Grand Prix in Stuttgart, losing in three sets to Petra Kvitová. However, she bounced back at the Madrid Open, where she cruised through her first three matches against Kateřina Siniaková, Jeļena Ostapenko, and Anastasija Sevastova. In the quarterfinals, she avenged both the loss in last year’s final and the loss in Stuttgart against Kvitová, beating the Czech, losing just five games. In the semifinals, she beat Sloane Stephens for the first time in her career, reaching a second consecutive Madrid final. There, she beat world No. 3 Simona Halep in straight sets, winning her first Premier Mandatory title, beating four former Grand Slam champions along the way and becoming the first to win Madrid without dropping a set. By doing so, she reached a new career-high ranking of No. 4.