The aim of this study was to understand how training and playing conditions during the COVID-19 pandemic affected the performance of Euroleague Basketball players. Using a non-participant observation analysis, the study compared the seasons before the lockdown with the season after restart. Paired t-tests and Wilcoxon tests were applied for variables with normal and non-normal distributions, respectively. The results revealed significant changes in several offensive and defensive performance-related variables during pandemic times : free throw attempts, free throw percentage, turnovers, three-point (...) attempt rate, fouls, points, and possessions. The pre-pandemic HA significantly decreased after the lockdown, with games played with no crowd. The one-sample t-test showed that the HA after the COVID-19 interruption was not significantly greater than 50%, indicating that the HA did not endure during the pandemic condition. Although significant differences between home and away teams were found for most performance-related variables in both pre-pandemic and pandemic conditions, variations of the relative HA were only significant for free throw attempts, points, and turnovers. The results of this study showed that performance variables were affected by the COVID-19 lockdown. Thus, these findings may help coaches, players, and referees to counteract unwanted competitive events and improve their overall performance, regardless of the contextual/situational circumstances encountered. (shrink)