Stupaczuk/Yanguas should enter as the more structurally solid pair: faster in transition, cleaner at net, and better equipped to dictate with sustained volley pressure in Valladolid’s quicker indoor-style conditions. Gil/Castaño can compete if they extend rallies and turn the match into a physical, high-lob grind, but they’ll likely struggle to win enough neutral points against Stupa’s countering and Yanguas’ right-side volume. Prediction: Stupaczuk/Yanguas in 2 sets, with a tight opener if Gil/Castaño start hot on serve.