In human-human interactions, the situational context plays a large role in the degree of speakers’ accommodation. In this paper, we investigate whether the degree of accommodation in a human-robot computer game is affected by (a) the duration of the interaction and (b) the success of the players in the game. 30 teams of two players played two card games with a conversational robot in which they had to find a correct order of five cards. After game 1, the players received the result of the game on a success scale from 1 (lowest success) to 5 (highest). Speakers’ f_o accommodation was measured as the Euclidean distance between the human speakers and each human and the robot. Results revealed that (a) the duration of the game had no influence on the degree of f_o accommodation and (b) the result of Game 1 correlated with the degree of f_o accommodation in Game 2 (higher success equals lower Euclidean distance). We argue that game success is most likely considered as a sign of the success of players’ cooperation during the discussion, which leads to a higher accommodation behavior in speech.