Namioka spaces, GO-spaces and an o-game

We introduce and study a new modification of the classical weak Choquet game which we call by an o-game. We show that this game coincides with the σ-game in the class of GO-spaces. Moreover, we obtain a wide class non-Namioka Baire spaces and characterize Namioka spaces in terms of topological games in the class of GO-spaces which can be represented as union of ω1 nowhere dense sets.