Powerful ultrashort pulses in the deep-ultraviolet (deep-UV) are beneficial for diverse applications from fundamental science to industrial materials processing. However, reaching high powers via conventional approaches is challenging due to three central issues: dispersion, multiphoton absorption, and optical damage. Here, we simultaneously overcome these issues with a novel fifth-harmonic generation architecture optimized for group velocity matching. We use tilted pulse fronts, including a noncollinear geometry in the final sum-frequency generation stage. This enables lower intensities and longer crystals, thereby favoring the birefringently phase matched