The effects of real-world events on the dynamics and sentiment expressed through online conversations is not entirely understood. In particular, the dynamics of highly polarized communities, deeply invested in the outcome of a particular event naturally tend to have a contrasting emotional sensitivity to exogenous events. In this study, we analyze Twitter conversations during the Mexico vs Germany group match of the 2018 FIFA World Cup, and investigate the effect of the live game outcomes on the conversation dynamics and sentiment. We find that the exogenous events influence conversation volume and virality less, while having high influence on user responsiveness. Interestingly, we observe a shift in the influence that exogenous events have on fans immediately following the only goal scored in the game. The emotional resilience of fans of the advantaged team increased following this exogenous shock. In contrast, the sentiment of the disadvantaged team was left more susceptible to further exogenous events following the exogenous shock. These results support the fact that user engagement and emotional resilience of an online population holding highly polarized stances can be manipulated through an exogenous event of high importance.