In this study, we analyzed one month of Call Detail Records, covering Budapest in June, 2016. During this observation period, the 2016 UEFA European Football Championship took place, where the Hungarian national football team did well, beyond expectations. This case study focuses on the fans' behavior in Budapest, during and after the Hungarian matches, from the perspective of the mobile phone network data. Tense rooting, joy of scoring a goal, self-forgetting celebration because of winning the group. All of these have an effect on the data, that can be simply revealed. We used descriptive statistical methods to analyze the available data set, and managed to demonstrate the potential of this kind of data at social sensing. We found that the mobile phone network activity reflects the football fans' behavior, even if the match is played in another country.