Oomycetes, also known as water molds, can infect a wide range of plants and animals, with some members eliciting the most destructive plant diseases and posing severe threats to global food security and natural ecosystems. Breeding resistant cultivars is the most efficient measure for managing the diseases instigated by oomycetes, but the success of the endeavor requires a sound and deep understanding of the molecular basis underlying pathogen–host interactions. In their new Spotlight comment titled "An epic war between an oomycete pathogen and plants", Zhengquin Fu and his collaborators highlight and discuss a recent study from Sun et al. published in Nature that used structural biology to identify the molecular mechanims mediating oomycete–host interactions. The new insights and resources gained from this study may be harnessed for more effective control of plant pathogens in the future.