Full title: "Enabling first-principles predictions of core performance in tokamaks with surrogate optimization techniques." This talk given by Pablo Rodríguez-Fernández introduced the need for flux-driven simulations to enable profile predictions, presented the fundamentals of the novel PORTALS technique, and discussed recent applications: the study of performance of burning plasmas in ITER and SPARC and the validation of ion-scale gyrokinetics in DIII-D and JET experiments.