Namioka spaces and topological games

We introduce a class of β − v-unfavourable spaces, which contains some known classes of β-unfavourable spaces for topological games of Choquet type. It is proved that every β − v-unfavourable space X is a Namioka space, that is for any compact space Y and any separately continuous function f : x × Y → ℝ there exists a dense in XGδ-set A ⊆ X such that f is jointly continuous at each point of A × Y.